I have been working on this for a while now but I do not seem to be able to resolve this bug. Any insights will be greatly appreciated thanks.
I am writing code that will parse a string first by ";" and then by " ". The code I have below is as follows:
void arrayVis(char **arr, int size){
printf("[");
for(int i = 0; i < size; i++){
if(arr[i] == NULL || strcmp(arr[i], "") == 0){
break;
}
printf("%s,", arr[i]);
}
void parser2(char *line){
char *token = strtok(line, " ");
char *arr[10];
int index = 0;
while(token != NULL){
arr[index] = token;
token = strtok(NULL, " ");
index++;
}
arrayVis(arr, 10);
}
void parser1(char *line){
char *token = strtok(line, ";");
while(token != NULL){
parser2(token);
// myPrint(token);
printf("\n");
token = strtok(NULL, ";");
}
}
array vis will just allow me to visualize the array that is produced. When I pass "1 2 3;4 5 6;"
I am expecting an output of
[1,2,3
[4,5,6
but instead I just get the output
[1,2,3
Why is my output omitting the second portion of the parse? I have been thinking about this for a while now but I dont seem to understand why this happens. Any insights will be appreciated. Thank you.
int main(void) {
static const char *ROW_TOKENS=";";
static const char *COL_TOKENS=" ";
char buf[] = "data1;data2 data3;data4 data5";
char *aux_row,*cursor_row;
cursor_row = strtok_r(buf, ROW_TOKENS, &aux_row);
// printf("[A] buf: %p, cursor_row=%p, aux_row=%p\n", buf, cursor_row, aux_row);
while (cursor_row) {
char *aux_col,*cursor_col;
printf("[");
cursor_col = strtok_r(cursor_row, COL_TOKENS, &aux_col);
// printf("[B] cursor_row=%p, aux_row=%p, cursor_col=%p, aux_col=%p\n",
// cursor_row, aux_row, cursor_col, aux_col);
while (cursor_col) {
// printf("[C] cursor_row=%p, aux_row=%p, cursor_col=%p, aux_col=%p\n",
// cursor_row, aux_row, cursor_col, aux_col);
printf("%s,", cursor_col);
cursor_col = strtok_r(NULL, COL_TOKENS, &aux_col);
}
cursor_row = strtok_r(NULL, ROW_TOKENS, &aux_row);
printf("\n");
}
return 0;
}
Related
I have to write this code, I mean I should read from the file name of students and their mark, and then sort students by the grow of mark. Now I just want to output only mark. I want to display grades using structures. I don't know where the problem is.
text.file
Jon 3
Alina 5
Ron 1
#include <stdio.h>
#define _CRT_SECURE_NO_WARNINGS
#include <string.h>
#include <stdlib.h>
int main()
{
const int N = 3;
int i = 0;
struct student {
char surname[50];
int mark;
};
struct student PI1[N];
char str[50];
const char s[1] = " ";
char* token;
FILE* ptr;
token = strtok(str, s);
ptr = fopen("test.txt", "r");
if (NULL == ptr) {
printf("file can't be opened \n");
}
while (fgets(str, 50, ptr) != NULL){
token = strtok(str, s);
strcpy(PI1[i].surname, token);
token = strtok(NULL, s);
PI1[i].mark = atoi(token);
i++;
}
fclose(ptr);
printf("The marks is:\n");
printf("%d %d %d", PI1[0].mark, PI1[1].mark, PI1[2].mark);
return 0;
}
You need to prevent the program from reading from the file pointer if opening the file fails:
ptr = fopen("test.txt", "r");
if (NULL == ptr) {
perror("test.txt");
return 1; // this could be one way
}
The second argument to strok should be a null terminated string. const char s[1] = " "; only has room for one character. No null terminator (\0). Make it:
const char s[] = " "; // or const char s[2] = " "; or const char *s = " ";
Don't iterate out of bounds. You need to check so that you don't try to put data in PI1[N] etc.
while (i < N && fgets(str, sizeof str, ptr) != NULL) {
// ^^^^^^^^
Check that strok actually returns a pointer to a new token. If it doesn't, the line you've read doesn't fulfill the requirements.
while (i < N && fgets(str, sizeof str, ptr) != NULL) {
token = strtok(str, s);
if(!token) break; // token check
strcpy(PI1[i].surname, token);
token = strtok(NULL, s);
if (token) // token check
PI1[i].mark = atoi(token);
else
break;
i++;
}
You could also skip the strcpy by reading directly into your struct student since char str[50]; has the same length as surname. str should probably be larger though, but for now:
while (i < N && fgets(PI1[i].surname, sizeof PI1[i].surname, ptr) != NULL) {
token = strtok(PI1[i].surname, s);
if(!token) break;
token = strtok(NULL, s);
if (token)
PI1[i].mark = atoi(token);
else
break;
i++;
}
Only print as many marks as you successfully read
printf("The marks are:\n");
for(int idx = 0; idx < i; ++idx) {
printf("%d ", PI1[idx].mark);
}
putchar('\n');
bellow is the code:
from some reason the calloc inside the while loop, is failing on the second iteration.
it looks the heap is corupted (not sure) but not clear the root cause.
please also take a look on the comment added there.
appriciate fast response.
#define _CRT_SECURE_NO_WARNINGS
#include <string.h>
#include<stdio.h>
#include <stdlib.h>
struct User_
{
char* id;
char* firstName;
char* lastName;
int age;
char gender[2];
char* userName;
char* password;
char* description;
char hobbies[2];
}typedef User;
void replaceEnterInString(int lengthString, char* string, int maxChars);
int main()
{
char str1[500] = "012345678;danny;cohen;22;M;danny1993;123;1,2,4,8;Nice person";
char str2[500] = "223325222;or;dan;25;M;ordan10;1234;3,5,6,7;Singer and dancer";
int j = 0;
char *token = NULL, arrangingHobbies;
int lengthStr, tempAge, hobby[4], i;
while(j<2)
{
User* newUser = NULL;
here it pass on first time but fail on second time. but only when adding the code that map the token to the newUser. without the mapping - do manage to calloc the user again and again as much as needed
error code: Critical error detected c0000374 - TEST.exe has triggered a breakpoint.
newUser = (User*)calloc(1, sizeof(User));
if (newUser == NULL)
{
printf("error");
exit(1);
}
//start map string to user
if (j == 0)
{
token = strtok(str1, ";");
printf("%s", str1);
}
else {
token = strtok(str2, ";");
printf("%s", str2);
}
//Input ID
newUser->id = (char*)calloc(10, sizeof(char));
if (newUser->id == NULL)
{
printf("error");
exit(1);
}
strcpy(newUser->id, token);
//Input first name
token = strtok(NULL, ";");
lengthStr = strlen(token);
newUser->firstName = (char*)calloc((lengthStr + 1), sizeof(char));
if (newUser->firstName == NULL)
{
printf("error");
exit(1);
}
strcpy(newUser->firstName, token);
//Input last name
token = strtok(NULL, ",;");
lengthStr = strlen(token);
newUser->lastName = (char*)calloc((lengthStr + 1), sizeof(char));
if (newUser->lastName == NULL)
{
printf("error");
exit(1);
}
strcpy(newUser->lastName, token);
//Input Age
token = strtok(NULL, ",;");
tempAge = atoi(token);
newUser->age = tempAge;
//Input gender
token = strtok(NULL, ",;");
newUser->gender[0] = token[0];
//Input User Name
token = strtok(NULL, ",;");
lengthStr = strlen(token);
newUser->userName = (char*)calloc((lengthStr), sizeof(char));
if (newUser->userName == NULL)
{
printf("error");
exit(1);
}
strcpy(newUser->userName, token);
//Input password
token = strtok(NULL, ",;");
lengthStr = strlen(token);
newUser->password = (char*)calloc((lengthStr), sizeof(char));
if (newUser->password == NULL)
{
printf("error");
exit(1);
}
strcpy(newUser->password, token);
//Input hobbies
newUser->hobbies[0] = 0;
for (i = 0; i < 4; ++i)
{
token = strtok(NULL, ",;");
tempAge = atoi(token);
arrangingHobbies = 1;
arrangingHobbies <<= (tempAge - 1);
newUser->hobbies[0] |= arrangingHobbies;
}
//Input description
token = strtok(NULL, ",;");
newUser->description = (char*)calloc((lengthStr), sizeof(char));
if (newUser->description == NULL)
{
printf("error");
exit(1);
}
replaceEnterInString(strlen(token), token, 300);
strcpy(newUser->description, token);
j++;
}
}
void replaceEnterInString(int lengthString, char* string, int maxChars)
{
if (lengthString < maxChars)
{
//remove the /n
string[lengthString - 1] = '\0';
}
}
Maybe there are other issues as well, yet the following code leads to undefined behaviour for sure:
lengthStr = strlen(token);
newUser->userName = (char*)calloc((lengthStr), sizeof(char));
...
strcpy(newUser->userName, token);
In previous similar statements, you correctly wrote ... = (char*)calloc((lengthStr+1), sizeof(char));.
BTW: In C, you usually don't cast the results of malloc, sizeof(char) is always 1 by definition, and there is no need for setting memory to 0 using calloc if you fill the memory with a subsequent strcpy anyway. So you should write...
lengthStr = strlen(token);
newUser->userName = malloc(lengthStr+1);
...
strcpy(newUser->userName, token);
Look through your code for similar issues, please.
I'm writing a basic program that takes a CSV file, prints the first field, and does some numerical evaluation of the other fields.
I'm looking to put all the numerical fields into an array but every time I do this and try to access a random element of the array, it prints the entire thing
My CSV file is:
Exp1,10,12,13
Exp2,15,16,19
and i'm trying to access the second field so it prints
Exp1 12
Exp2 16
but instead I'm getting
Exp1 101213
Exp2 151619
If someone could provide some suggestions. This is my code:
#define DELIM ","
int main(int argc, char *argv[])
{
if(argc == 2) {
FILE *txt_file;
txt_file = fopen(argv[1], "rt");
if(!txt_file) {
printf("File does not exist.\n");
return 1;
}
char tmp[4096];
char data[4096];
char expName[100];
char *tok;
int i;
while(1){
if(!fgets(tmp, sizeof(tmp), txt_file)) break;
//prints the experiment name
tok = strtok(tmp, DELIM);
strncpy(expName, tok, sizeof(expName));
printf("\n%s ", expName);
while(tok != NULL) {
tok = strtok(NULL, DELIM);
//puts data fields into an array
for(i=0; i < sizeof(data); i++) {
if(tok != NULL) {
data[i] = atoi(tok);
}
}
printf("%d", data[1]);
}
}
fclose(txt_file);
return 0;
}
sample to fix
char tmp[4096];
int data[2048];
char expName[100];
char *tok;
int i=0;
while(fgets(tmp, sizeof(tmp), txt_file)){
tok = strtok(tmp, DELIM);
strncpy(expName, tok, sizeof(expName));
printf("\n%s ", expName);
while((tok = strtok(NULL, DELIM))!=NULL){
data[i++] = atoi(tok);
}
printf("%d", data[1]);
i = 0;
}
A modified code snippet:
int data[20]; // change 20 to a reasonable value
...
while (1)
{ if (!fgets(tmp, sizeof(tmp), txt_file))
break;
//prints the experiment name
tok = strtok(tmp, DELIM);
strncpy(expName, tok, sizeof(expName));
printf("\n%s ", expName);
i = 0;
tok = strtok(NULL, DELIM);
while (tok != NULL)
{ //puts data fields into an array
data[i++] = atoi(tok);
if (i == 20)
break;
tok = strtok(NULL, DELIM);
}
if (i > 1)
printf("%d", data[1]);
}
I'm having some issues trying to print out an array of characters (storage) that hold tokens (tok). Everytime I print the array I get a strange symbol.
while(1)
{
printf("repl>");
char storage [30];
char* tok;
char g;
char buffer[20];
int pos = 0, i;
size_t bufferlength = 20;
fgets(buffer,sizeof(buffer),stdin);
tok = strtok(buffer," ");
while (tok != NULL)
{
storage[pos] = tok;
tok = strtok(NULL," ");
pos++;
}
printf(" %c\n", storage[0]);
}
I am having trouble with the strtok function. I keep getting a 'bus error.' I wrote a function to return all the words within a line. Could somebody please point out my error?
NOTE: I am used to higher level languages
void extract_words(char tokens[WORD_MAX][WORD_LEN], char* line, int* sizePtr)
{
printf("in extract words"); //for debugging
char* chPtr = NULL;
chPtr = strtok(line, " ");
int size = 1; //words has one element
while(chPtr != NULL)
{
strcpy(tokens[size++], chPtr);
chPtr = strtok(NULL, " "); //continue to tokenize the string
}
*sizePtr = size;
}
Thanks in advance!
strtok modifies the string you pass to it, so it can't be a string literal. You should be able to do something like this:
void extract_words(char tokens[WORD_MAX][WORD_LEN], const char* line_arg, int* sizePtr)
{
char line[(WORD_LEN+1)*WORD_MAX];
char* chPtr = NULL;
int size = 0;
strcpy(line,line_arg);
printf("in extract words"); //for debugging
chPtr = strtok(line, " ");
while(chPtr != NULL)
{
strcpy(tokens[size++], chPtr);
chPtr = strtok(NULL, " "); //continue to tokenize the string
}
*sizePtr = size;
}
Note that I also initialized size to zero, since array indices start at zero.
Well...
Should you try to use a separator?
That case, I have source code.
int split(char *src, char *div, char **result,int *size)
{
int i, j, slen, dlen, key=0, start=0;
slen=strlen(src);
dlen=strlen(div);
for(i=0;i<slen;i++)
{
for(j=0;j<dlen;j++)
{
if(src[i]==div[j])
{
src[i]=0x00;
result[key] = src+start;
key++;
start=i+1;
}
}
}
result[key]=src+start;
*size=key+1;
return 0;
}
using
split(chatData, " ", cmpData, &tok);
" " : token
&tok : count split word
chatData : original data
by korean Dalsam.