I have input like the following:
Someting sth
example
5 15
3
I want to scanf input by lines to get whole content of the line. But when reaching first digit (there can be spaces/tabs before it) I want to scanf it as int.
That's what I have come up with but it does not work as expected - cursor still does not stop at digit character.
char person_name[1000];
int n;
while (scanf("%[^\n/D]%*c", person_name) > 0) {
if (checkIfContainsNumber(person_name) == 0) {
appendToLinkedList(&head_ref, person_name);
} else {
break;
}
}
while (scanf("%d", &n) > 0) {
printf("%d ", n);
}
As far as I understand the problem, each line could be considered either as
a sequence of names or a sequence of integers.
So I would try to read the file line by line and analyse each extracted line
as one sequence or another (spaces are implicitly consumed).
The trick here is the usage of "%n" to go further in the analyse of the same line.
#include <stdio.h>
int
main(void)
{
FILE *input=fopen("input.txt", "r");
if(!input)
{
return 1;
}
char line[1024];
while(fgets(line, sizeof(line), input))
{
int pos=0;
int value, count;
char name[256];
if(sscanf(line+pos, "%d%n", &value, &count)==1)
{
pos+=count;
printf("a line with values: <%d>", value);
while(sscanf(line+pos, "%d%n", &value, &count)==1)
{
pos+=count;
printf(" <%d>", value);
}
printf("\n");
}
else if(sscanf(line+pos, "%255s%n", name, &count)==1)
{
pos+=count;
printf("a line with names: <%s>", name);
while(sscanf(line+pos, "%255s%n", name, &count)==1)
{
pos+=count;
printf(" <%s>", name);
}
printf("\n");
}
}
fclose(input);
return 0;
}
Read the input line-wise with fgets and keep a mode: TEXT for text, NUMBER for numbers and ERROR for an error condition. (The error condition is undescribed. It could occur when you encounter non-numeric data in NUMBER mode, for example.)
Start out with TEXT. Before processing a line in text mode, check whether it could be a digit by a simple sscanf into the line. If you can read a number, switch to number mode, where you scan all numbers from a line.
char line[80];
enum {TEXT, NUMBER, ERROR = -1} mode = TEXT;
while (mode != ERROR && fgets(line, sizeof(line), stdin)) {
if (mode == TEXT) {
int n;
if (sscanf(line, "%d", &n) > 0) mode = NUMBER;
}
if (mode == TEXT) {
line[strcspn(line, "\n")] = '\0';
process_string(line);
} else if (mode == NUMBER) {
char *p = line;
char *end;
int n = strtol(p, &end, 0);
if (end == p) mode = ERROR;
while (end > p) {
process_number(n);
p = end;
n = strtol(p, &end, 0);
}
}
}
(But this approach will fail if the numbers are all in one very long. fgets truncates the input so that the specified size will nor be exceeded.)
Consider changing the scan strategy - ignore all characters that are non-digit, and then read the integer from that digits forward
if ( scanf("%*[^0-9]%d", &n) == 1 ) { ... }
The first field '%*[...]' will skip over anything that is non-digit. Note that it's possible to reach EOF before finding a digit - if statement is needed to check.
Related
I've been trying to input 2 char arrays from user.
I want to truncate the input characters if they are more than specified length.
This is what I have done so far.
int main(){
printf("Enter Password: ");
char password[9]= {0};
fgets(password, sizeof(password), stdin);
printf("Enter key file path: ");
char file_path[200];
fflush(stdin);
fgets(file_path, sizeof(file_path), stdin);
puts(file_path);
return 0;
}
I get this output:
If I enter more than 8 chars, it automatically assigns charcaters above 8 to my file_path. It does not ask for the 2nd input!
PS: I tried scanf("%8s", password) instead of fgets. Same issue.
Please Help, Thanks
In OP's code, the input that does not fit in the first fgets() remains for subsequent input. Better code would consume the entire line and detect if the line is excessively long.
Use fgets() with a long enough buffer to look for incomplete line input.
Read at least 2 more characters: extra character and '\n'.
Perhaps use your own my_gets() to read a line.
// Read a line
// If input, without the \n fits in the destination, return `s`
// else return NULL
// Conditions: line != NULL, 0 < sz <= INT_MAX
char *my_gets(char *line, size_t sz) {
if (fgets(line, (int) sz, stdin) == NULL) {
line[0] = '\0';
return NULL; // EOF
}
size_t length = strlen(line);
if (length > 0 && line[length - 1] == '\n') {
line[--length] = '\0'; // Chop off \n
} else if (length == sz - 1) {
// Consume rest of line
bool looped = false;
int ch;
while ((ch = fgetc(stdin)) != '\n' && ch != EOF) {
looped = true;
}
if (looped) {
return NULL; // Line too long
}
}
return line;
}
Application
int main(void) {
printf("Enter Password: ");
char password[9];
if (my_gets(password, sizeof password) == NULL) {
return EXIT_FAILURE;
}
puts(password);
printf("Enter key file path: ");
char file_path[200];
if (my_gets(file_path, sizeof file_path) == NULL) {
return EXIT_FAILURE;
}
puts(file_path);
return EXIT_SUCCESS;
}
From a security standpoint, good to scrub password[] and line[] after code is done with it.
memset(password, 0, sizeof password);
Yet the call to fgets(), fgetc() are themselves not so secure as they are not specified to "cover their tracks" as they return. This is a deeper subject beyond this post.
I made this code:
/*here is the main function*/
int x , y=0, returned_value;
int *p = &x;
while (y<5){
printf("Please Insert X value\n");
returned_value = scanf ("%d" , p);
validate_input(returned_value, p);
y++;
}
the function:
void validate_input(int returned_value, int *p){
getchar();
while (returned_value!=1){
printf("invalid input, Insert Integers Only\n");
getchar();
returned_value = scanf("%d", p);
}
}
Although it is generally working very well but when I insert for example "1f1" , it accepts the "1" and does not report any error and when insert "f1f1f" it reads it twice and ruins the second read/scan and so on (i.e. first read print out "invalid input, Insert Integers Only" and instead for waiting again to re-read first read from the user, it continues to the second read and prints out again "invalid input, Insert Integers Only" again...
It needs a final touch and I read many answers but could not find it.
If you don't want to accept 1f1 as valid input then scanf is the wrong function to use as scanf returns as soon as it finds a match.
Instead read the whole line and then check if it only contains digits. After that you can call scanf
Something like:
#include <stdio.h>
int validateLine(char* line)
{
int ret=0;
// Allow negative numbers
if (*line && *line == '-') line++;
// Check that remaining chars are digits
while (*line && *line != '\n')
{
if (!isdigit(*line)) return 0; // Illegal char found
ret = 1; // Remember that at least one legal digit was found
++line;
}
return ret;
}
int main(void) {
char line[256];
int i;
int x , y=0;
while (y<5)
{
printf("Please Insert X value\n");
if (fgets(line, sizeof(line), stdin)) // Read the whole line
{
if (validateLine(line)) // Check that the line is a valid number
{
// Now it should be safe to call scanf - it shouldn't fail
// but check the return value in any case
if (1 != sscanf(line, "%d", &x))
{
printf("should never happen");
exit(1);
}
// Legal number found - break out of the "while (y<5)" loop
break;
}
else
{
printf("Illegal input %s", line);
}
}
y++;
}
if (y<5)
printf("x=%d\n", x);
else
printf("no more retries\n");
return 0;
}
Input
1f1
f1f1
-3
Output
Please Insert X value
Illegal input 1f1
Please Insert X value
Illegal input f1f1
Please Insert X value
Illegal input
Please Insert X value
x=-3
Another approach - avoid scanf
You could let your function calculate the number and thereby bypass scanf completely. It could look like:
#include <stdio.h>
int line2Int(char* line, int* x)
{
int negative = 0;
int ret=0;
int temp = 0;
if (*line && *line == '-')
{
line++;
negative = 1;
}
else if (*line && *line == '+') // If a + is to be accepted
line++; // If a + is to be accepted
while (*line && *line != '\n')
{
if (!isdigit(*line)) return 0; // Illegal char found
ret = 1;
// Update the number
temp = 10 * temp;
temp = temp + (*line - '0');
++line;
}
if (ret)
{
if (negative) temp = -temp;
*x = temp;
}
return ret;
}
int main(void) {
char line[256];
int i;
int x , y=0;
while (y<5)
{
printf("Please Insert X value\n");
if (fgets(line, sizeof(line), stdin))
{
if (line2Int(line, &x)) break; // Legal number - break out
printf("Illegal input %s", line);
}
y++;
}
if (y<5)
printf("x=%d\n", x);
else
printf("no more retries\n");
return 0;
}
Generally speaking, it is my opinion that you are better to read everything from the input (within the range of your buffer size, of course), and then validate the input is indeed the correct format.
In your case, you are seeing errors using a string like f1f1f because you are not reading in the entire STDIN buffer. As such, when you go to call scanf(...) again, there is still data inside of STDIN, so that is read in first instead of prompting the user to enter some more input. To read all of STDIN, you should do something the following (part of code borrowed from Paxdiablo's answer here: https://stackoverflow.com/a/4023921/2694511):
#include <stdio.h>
#include <string.h>
#include <stdlib.h> // Used for strtol
#define OK 0
#define NO_INPUT 1
#define TOO_LONG 2
#define NaN 3 // Not a Number (NaN)
int strIsInt(const char *ptrStr){
// Check if the string starts with a positive or negative sign
if(*ptrStr == '+' || *ptrStr == '-'){
// First character is a sign. Advance pointer position
ptrStr++;
}
// Now make sure the string (or the character after a positive/negative sign) is not null
if(*ptrStr == NULL){
return NaN;
}
while(*ptrStr != NULL){
// Check if the current character is a digit
// isdigit() returns zero for non-digit characters
if(isdigit( *ptrStr ) == 0){
// Not a digit
return NaN;
} // else, we'll increment the pointer and check the next character
ptrStr++;
}
// If we have made it this far, then we know that every character inside of the string is indeed a digit
// As such, we can go ahead and return a success response here
// (A success response, in this case, is any value other than NaN)
return 0;
}
static int getLine (char *prmpt, char *buff, size_t sz) {
int ch, extra;
// Get line with buffer overrun protection.
if (prmpt != NULL) {
printf ("%s", prmpt);
fflush (stdout);
}
if (fgets (buff, sz, stdin) == NULL)
return NO_INPUT;
// If it was too long, there'll be no newline. In that case, we flush
// to end of line so that excess doesn't affect the next call.
// (Per Chux suggestions in the comments, the "buff[0]" condition
// has been added here.)
if (buff[0] && buff[strlen(buff)-1] != '\n') {
extra = 0;
while (((ch = getchar()) != '\n') && (ch != EOF))
extra = 1;
return (extra == 1) ? TOO_LONG : OK;
}
// Otherwise remove newline and give string back to caller.
buff[strlen(buff)-1] = '\0';
return OK;
}
void validate_input(int responseCode, char *prompt, char *buffer, size_t bufferSize){
while( responseCode != OK ||
strIsInt( buffer ) == NaN )
{
printf("Invalid input.\nPlease enter integers only!\n");
fflush(stdout); /* It might be unnecessary to flush here because we'll flush STDOUT in the
getLine function anyway, but it is good practice to flush STDOUT when printing
important information. */
responseCode = getLine(prompt, buffer, bufferSize); // Read entire STDIN
}
// Finally, we know that the input is an integer
}
int main(int argc, char **argv){
char *prompt = "Please Insert X value\n";
int iResponseCode;
char cInputBuffer[100];
int x, y=0;
int *p = &x;
while(y < 5){
iResponseCode = getLine(prompt, cInputBuffer, sizeof(cInputBuffer)); // Read entire STDIN buffer
validate_input(iResponseCode, prompt, cInputBuffer, sizeof(cInputBuffer));
// Once validate_input finishes running, we should have a proper integer in our input buffer!
// Now we'll just convert it from a string to an integer, and store it in the P variable, as you
// were doing in your question.
sscanf(cInputBuffer, "%d", p);
y++;
}
}
Just as a disclaimer/note: I have not written in C for a very long time now, so I do apologize in advance if there are any error in this example. I also did not have an opportunity to compile and test this code before posting because I am in a rush right now.
If you're reading an input stream that you know is a text stream, but that you are not sure only consists of integers, then read strings.
Also, once you've read a string and want to see if it is an integer, use the standard library conversion routine strtol(). By doing this, you both get a confirmation that it was an integer and you get it converted for you into a long.
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
bool convert_to_long(long *number, const char *string)
{
char *endptr;
*number = strtol(string, &endptr, 10);
/* endptr will point to the first position in the string that could
* not be converted. If this position holds the string terminator
* '\0' the conversion went well. An empty input string will also
* result in *endptr == '\0', so we have to check this too, and fail
* if this happens.
*/
if (string[0] != '\0' && *endptr == '\0')
return false; /* conversion succesful */
return true; /* problem in conversion */
}
int main(void)
{
char buffer[256];
const int max_tries = 5;
int tries = 0;
long number;
while (tries++ < max_tries) {
puts("Enter input:");
scanf("%s", buffer);
if (!convert_to_long(&number, buffer))
break; /* returns false on success */
printf("Invalid input. '%s' is not integer, %d tries left\n", buffer,
max_tries - tries);
}
if (tries > max_tries)
puts("No valid input found");
else
printf("Valid input: %ld\n", number);
return EXIT_SUCCESS;
}
ADDED NOTE: If you change the base (the last parameter to strtol()) from 10 to zero, you'll get the additional feature that your code converts hexadecimal numbers and octal numbers (strings starting with 0x and 00 respectively) into integers.
I took #4386427 idea and just added codes to cover what it missed (leading spaces and + sign), I tested it many times and it is working perfectly in all possible cases.
#include<stdio.h>
#include <ctype.h>
#include <stdlib.h>
int validate_line (char *line);
int main(){
char line[256];
int y=0;
long x;
while (y<5){
printf("Please Insert X Value\n");
if (fgets(line, sizeof(line), stdin)){//return 0 if not execute
if (validate_line(line)>0){ // check if the string contains only numbers
x =strtol(line, NULL, 10); // change the authentic string to long and assign it
printf("This is x %d" , x);
break;
}
else if (validate_line(line)==-1){printf("You Have Not Inserted Any Number!.... ");}
else {printf("Invalid Input, Insert Integers Only.... ");}
}
y++;
if (y==5){printf("NO MORE RETRIES\n\n");}
else{printf("%d Retries Left\n\n", (5-y));}
}
return 0;}
int validate_line (char *line){
int returned_value =-1;
/*first remove spaces from the entire string*/
char *p_new = line;
char *p_old = line;
while (*p_old != '\0'){// loop as long as has not reached the end of string
*p_new = *p_old; // assign the current value the *line is pointing at to p
if (*p_new != ' '){p_new++;} // check if it is not a space , if so , increment p
p_old++;// increment p_old in every loop
}
*p_new = '\0'; // add terminator
if (*line== '+' || *line== '-'){line++;} // check if the first char is (-) or (+) sign to point to next place
while (*line != '\n'){
if (!(isdigit(*line))) {return 0;} // Illegal char found , will return 0 and stop because isdigit() returns 0 if the it finds non-digit
else if (isdigit(*line)){line++; returned_value=2;}//check next place and increment returned_value for the final result and judgment next.
}
return returned_value; // it will return -1 if there is no input at all because while loop has not executed, will return >0 if successful, 0 if invalid input
}
I want to write a code to ensure that the users input only 1 digit. If a user enters something like "0 1 3" I want my program to read an error message which I have no idea how to do. Anyone has an idea how to approach this? My current code just takes in the first number if a user enters bunch of numbers with a space in between.
Please see my code below. Thanks :D
//Prompt the user to enter the low radius with data validation
printf("Enter the low radius [0.0..40.0]: ");
do
{
ret = scanf("%lf", &lowRadius);
//type validation
if (ret != 1)
{
int ch = 0;
while (((ch = getchar()) != EOF) && (ch != '\n'));
printf("Wrong input. Please enter one numerical value: ");
}
//range validation
else if((lowRadius < 0 || lowRadius > 40))
{
printf("Incorrect value. Please enter in range 0-40: ");
}
else break;
} while ((ret != 1) || (lowRadius < 0 || lowRadius > 40));//end while lowRadius
If you read the line into a string, then analyse it, you avoid the problem of hanging on unsupplied input. You have done most of the work already, but this shows how to trap too much input. It works by scanning a string after the double to pick up any more input. The return value from sscanf tells you if there was, because it returns the number of items successfully scanned.
#include <stdio.h>
#include <stdlib.h>
void err(char *message)
{
puts(message);
exit(1);
}
int main(void)
{
double lowRadius = 0.0;
char inp[100];
char more[2];
int conv;
if(fgets(inp, sizeof inp, stdin) == NULL) {
err("Input unsuccesful");
}
conv = sscanf(inp, "%lf %1s", &lowRadius, more); // conv is number of items scanned
if(conv != 1) {
err("One input value is required");
}
if(lowRadius < 0.0 || lowRadius > 40.0) {
err("Number out of range");
}
printf("%f\n", lowRadius);
return 0;
}
I'm unsure about your stipulation of a single digit, since that won't allow your maximum value to be entered.
Read a whole line and convert it with strtod.
Alexander has the right approach, but doesn't give much detail. Here is how I would do it, using getline() to read the input, and then strspn() plus strtod() to parse the input that was read. If you are not familiar with working with pointers, this will be difficult to understand - but if you are learning C, you'll get there eventually:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void) {
double lowRadius;
char *lineptr = NULL;
size_t n;
char *startptr;
char *endptr;
char *ws = " \t\n"; /* possible whitespace characters */
printf("Enter the low radius [0.0..40.0]: ");
while(1) {
/* free lineptr if set - neeeded if we iterate on error input */
if( lineptr ) {
free(lineptr);
lineptr = NULL;
}
/* now read a line of input */
while( getline(&lineptr, &n, stdin) == -1 ) {
/* error returned, just retry */
continue;
}
/* skip over any leading whitespace */
startptr = lineptr + strspn(lineptr,ws);
/* Now try to convert double */
lowRadius = strtod(startptr, &endptr);
if( endptr==startptr || endptr[strspn(endptr,ws)] != 0 ) {
/* either no characters were processed - e.g., the
line was empty, or there was some non-whitespace
character found after the number. */
printf( "Wrong input. Please enter one numerical value: ");
} else if( (lowRadius < 0.0) || (lowRadius > 40.0) ) {
printf( "Incorrect value. Please enter in range 0-40: " );
} else {
if( lineptr ) free(lineptr);
break;
}
}
printf( "value entered was %lf\n", lowRadius );
}
I have a function to read a text file with the following format
string int int
string int int
string int int
I want to write a function that will assign the values from the text file into variables, but there will also be some cases where the format of the text file will be
string int
string int
string int
In that case, I'd like to set the value of the last int variable to 1. My code I have so far works with the first example but I'm a bit stuck on getting the second scenario to work:
void readFile(LinkedList *inList, char* file)
{
char tempName[30];
int tempLoc, tempNum;
FILE* f;
f = fopen(file, "r");
if(f==NULL)
{
printf("Error: could not open file");
}
else
{
while (fscanf(f, "%s %d %d\n", tempName, &tempLoc, &tempNum) != EOF)
{
insertFirst (inList, tempName, tempLoc, tempNum);
}
}
}
In the second case, fscanf will return 2 instead of 3. So you can rewrite the code like this:
while (1) {
int ret = fscanf(f, "%s %d %d\n", tempName, &tempLoc, &tempNum);
if (ret == EOF) {
break;
}
if (ret == 2) {
tempNum = 1;
} else if (ret != 3) {
// line appear invalid, deal with the error
}
insertFirst (inList, tempName, tempLoc, tempNum);
}
A more hacky way would be to set tempNum to 1 before calling fscanf and just check for EOF as you did above. But I think the code above is clearer.
Edit: to avoid overflows, this would be better. The code would perform better but this is harder to write. Just like above, I did not write any code for the error conditions but you definitely want to handle them
char lineBuf[255];
while (fgets(lineBuf, sizeof(lineBuf), f) != NULL) {
int spaceIdx, ret;
const int len = strlen(lineBuf);
if (len == (sizeof(lineBuf) - 1) {
// line is too long - either your buf is too small and you should tell the user
// that its input is bad
// I recommend to treat this as an error
}
lineBuf[len - 1] = '\0'; // remove \n
--len; // update len, we've removed one character
if (isspace(*lineBuf)) {
// error, line should not start with a space
}
spaceIdx = strcspn(lineBuf, "\t ");
if (spaceIdx == len) {
// error, no space in this line
}
// Ok, we've found the space. Deal with the rest.
// Note that for this purpose, sscanf is a bit heavy handed (but makes the code
// simpler). You could do it with strtol.
// Also, the first space in the format string is important, so sscanf skips
// all the space at the beginning of the string. If your format requires only
// one space between fields, you can do sscanf(lineBuf + spaceIdx + 1, "%d %d"...
ret = sscanf(lineBuf + spaceIdx, " %d %d", &tempLoc, &tempNum);
if (0 == ret) {
// error, no ints
}
else if (1 == ret) {
tempNum = 1;
}
// at that point, you could copy the first part of lineBuf to tempName, but then
// you have to deal with a potential overflow (and spend time on an useless copy),
// so use lineBuf instead
lineBuf[spaceIdx] = '\0';
insertFirst (inList, lineBuf, tempLoc, tempNum);
}
Well i have this code to find the paint quality of a room.
void get_room_size(char room_id, int * length, int * width) {
while (*length <= 0 && *width <= 0) {
printf("Enter length and width of room %c in feet: ", room_id);
if (scanf("%d,%d", length, width)) {
if (*length <= 0) {
printf("###Error! Length must be a positive value!\n");
}
if (*width <= 0) {
printf("###Error! Width must be a positive value!\n");
}
printf("\n");
} else {
printf("bad data");
*length = 0;
*width = 0;
}
}
}
Basically, if i enter
a,1
It will go crazy and keep looping. Whats the problem?
The reason it's going "crazy" is as follows. When scanf fails to read in a as a number (because it's not numeric, obviously), it won't advance the file pointer.
This is one reason why you shouldn't generally use scanf operations, a failure can leave the file pointer in an indeterminate position (such as if you only scan in 3 of 12 items).
The other reason is that scanf means "scan formatted" and you would be hard pressed finding anything more unformatted than user input.
Anyway, back to the failure. Because the file pointer isn't advanced, the next time you come back to do fscanf, it will try to read that a again (and again and again).
If you want a decent function for handling user input, look no further than here:
#include <stdio.h>
#include <string.h>
#define OK 0
#define NO_INPUT 1
#define TOO_LONG 2
static int getLine (char *prmpt, char *buff, size_t sz) {
int ch, extra;
// Get line with buffer overrun protection.
if (prmpt != NULL) {
printf ("%s", prmpt);
fflush (stdout);
}
if (fgets (buff, sz, stdin) == NULL)
return NO_INPUT;
// If it was too long, there'll be no newline. In that case, we flush
// to end of line so that excess doesn't affect the next call.
if (buff[strlen(buff)-1] != '\n') {
extra = 0;
while (((ch = getchar()) != '\n') && (ch != EOF))
extra = 1;
return (extra == 1) ? TOO_LONG : OK;
}
// Otherwise remove newline and give string back to caller.
buff[strlen(buff)-1] = '\0';
return OK;
}
This will input a line from the user, with overflow protection (unlike gets or scanf with unbounded "%s").
It also flushes to end of line if the input was too long, which will stop the remainder of the line from affecting the next input operation.
You can then sscanf the buffer to your heart's content without any concerns re the file pointer.
The following test program shows how to use this:
int main (void) {
int rc;
char buff[10];
rc = getLine ("Enter string> ", buff, sizeof(buff));
if (rc == NO_INPUT) {
// Extra NL since my system doesn't output that on EOF.
printf ("\nNo input\n");
return 1;
}
if (rc == TOO_LONG) {
printf ("Input too long [%s]\n", buff);
return 1;
}
printf ("OK [%s]\n", buff);
return 0;
}
As an aside, you may want to re-examine your logic for a valid sized room. What you currently have would allow a room to be entered as 7 by -42 feet :-)
It's also not usually good form to rely on the output values being set to specific values on entry. If length and width are (for example) 3 and 4 on entry, this function will exit straight away without asking the user for input.
The first problem can be fixed by using || instead of &&. The second by initialising the variables to 0 at the start of the function so that the loop is entered.
For completeness, if you combine that original snippet above (the include statements and the getLine() function) with the following slightly modified get_room_size() function:
static void get_room_size(char room_id, int * length, int * width) {
char buff[100];
*length = *width = 0;
while ((*length <= 0) || (*width <= 0)) {
printf("Enter length and width of room %c in feet: ", room_id);
int rc = getLine (NULL, buff, sizeof (buff));
if (rc == NO_INPUT) {
printf ("\nEnd of file encountered.\n");
return;
}
if (rc == TOO_LONG) {
printf ("\nInput too long, please retry.\n");
continue;
}
if (sscanf(buff, "%d,%d", length, width) != 2) {
*length = *width = 0;
printf ("\nInput not in desired form (<number>,<number>), "
"please retry.\n");
continue;
}
if ((*length <=0) || (*width <= 0)) {
*length = *width = 0;
printf ("\nBoth length and width must be greater than zero, "
"please retry.\n");
}
}
}
and the very simple test main(), you'll see a complete program showing how to do it.
int main (void) {
int len, wid;
get_room_size ('x', &len, &wid);
printf ("Length is %d, width is %d.\n", len, wid);
return 0;
}
your scanf is taking in two integer. A is a character, think you want to
scanf("%c", *room_id);
scanf("%d", length);
I reccommend you do them separately
Try this:
...
if (scanf("%d,%d", length, width) == 2) {
if (*length <= 0) {
printf("###Error! Length must be a positive value!\n");
}
if (*width <= 0) {
printf("###Error! Width must be a positive value!\n");
}
printf("\n");
} else {
printf("bad data");
*length = -1;
*width = -1;
}
You dont put & in scanf() statement so how its read
if (scanf("%d,%d", &length, &width))