I'm doing a program that is asking the user to enter a stream of characters and printing out the number of uppercase and lowercase letters. I'm trying to do it with a function, but having some trouble printing it..for every character input im entering im getting 0, 0
Would appreciate your help to understand what am I doing wrong:
#include <stdio.h>
#include <ctype.h>
int case_letters(int ch);
int main(void)
{
int x;
printf("please enter a some characters, and ctrl + d to see result\n");
case_letters(x);
return 0;
}
int case_letters(int ch)
{
int numOfUpper = 0;
int numOfLower = 0;
while ((ch = getchar()) != EOF)
{
if ((ch = isdigit(ch)) || ch == '\n')
{
printf("please enter a valid character\n");
continue;
}
else if ((ch = isupper(ch)))
{
numOfUpper++;
}
else if ((ch = islower(ch)))
{
numOfLower++;
}
}
return printf("%d, %d", numOfUpper, numOfLower);
}
All of your if statements assign different value to ch and do not check ch's value.
For example, if you enter a correct char, this
if ((ch = isdigit(ch)) || ch == '\n')
will assign 0 to ch, because isdigit(ch) will return 0. I guess you need
if ( isdigit(ch) || ch == '\n')
Same for islower and isupper.
if ((ch = isdigit(ch)) || ch == '\n')
^-- assignment, not equality test.
You're trashing the value of ch with the return value of isdigit(), and isupper(), and islower(), so that the original user-entered value is destroyed as soon as you do the isdigit test.
Try
if (isdigit(ch) || ch == '\n')
else if (isupper(ch))
else if (islower(ch))
instead. No need to preserve the iswhatever values.
Related
This code contains 3 file handling related functions which read from a file named "mno". But only the 1st called function in the main() is working. If the 1st function of the list is commented then, only the 2nd function will work and the third won't. Same goes for the 3rd one
#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
void countVowel(char fin[])
{
FILE *fl;
char ch;
int count = 0;
fl = fopen(fin, "r");
while (ch != EOF)
{
ch = tolower(fgetc(fl));
count += (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') ? 1 : 0;
}
fclose(fl);
printf("Number of Vowels in the file \" %s \"-> \t %d \n", fin, count);
}
void countConsonant(char fin[])
{
FILE *fl;
char ch;
int count = 0;
fl = fopen(fin, "r");
while (ch != EOF)
{
ch = tolower(fgetc(fl));
count += (!(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') && (ch >= 'a' && ch <= 'z')) ? 1 : 0;
}
fclose(fl);
printf("Number of Consonant in the file \" %s \"-> \t %d \n", fin, count);
}
void countAlphabet(char fin[])
{
FILE *fl;
char ch;
int count = 0;
fl = fopen(fin, "r");
while (ch != EOF)
{
ch = tolower(fgetc(fl));
count += (ch >= 'a' && ch <= 'z') ? 1 : 0;
}
fclose(fl);
printf("Number of Alphabets in the file \" %s \"-> \t %d \n", fin, count);
}
int main()
{
countVowel("mno"); // output -> 10
countConsonant("mno"); // output -> 0
countAlphabet("mno"); // output -> 0
return 0;
}
Here are the contents of "mno" file ->
qwertyuiopasdfghjklzxcvbnm, QWERTYUIOPASDFGHJKLZXCVBNM, 1234567890
As others have mentioned, your handling of EOF was incorrect:
ch was uninitialized on the first loop iteration
Doing tolower(fgetc(fl)) would obliterate the EOF value.
Using char ch; instead of int ch; would allow a [legitimate] 0xFF to be seen as an EOF.
But, it seems wasteful to have three separate functions to create the three different counts because the most time is spent in the I/O versus the determination of what type of character we're looking at. This is particularly true when the counts are so interelated.
We can keep track of multiple types of counts easily using a struct.
Here's a refactored version that calculates all three counts in a single pass through the file:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
struct counts {
int vowels;
int consonants;
int alpha;
};
void
countAll(const char *fin,struct counts *count)
{
FILE *fl;
int ch;
int vowel;
count->vowels = 0;
count->consonants = 0;
count->alpha = 0;
fl = fopen(fin, "r");
if (fl == NULL) {
perror(fin);
exit(1);
}
while (1) {
ch = fgetc(fl);
// stop on EOF
if (ch == EOF)
break;
// we only care about alphabetic chars
if (! isalpha(ch))
continue;
// got one more ...
count->alpha += 1;
ch = tolower(ch);
// is current character a vowel?
vowel = (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u');
// since we know it's alphabetic, it _must_ be either a vowel or a
// consonant
if (vowel)
count->vowels += 1;
else
count->consonants += 1;
}
fclose(fl);
printf("In the file: \"%s\"\n",fin);
printf(" Number of Vowels: %d\n",count->vowels);
printf(" Number of Consonants: %d\n",count->consonants);
printf(" Number of Alphabetics: %d\n",count->alpha);
}
int
main(void)
{
struct counts count;
countAll("mno",&count);
return 0;
}
For your given input file, the program output is:
In the file: "mno"
Number of Vowels: 10
Number of Consonants: 42
Number of Alphabetics: 52
You are using ch uninitialized. at while (ch != EOF). Every function call after the first has ch equal to 0 at the start, because you forgot to initialize it and the memory was set to -1 before. You can fix it by replacing the loops like this:
int ch;
...
while ((ch = fgetc(fl)) != EOF)
{
ch = tolower(ch);
count += ...;
}
Here ch is getting initialized before you check it and later converted to lowercase.
EDIT:
Note that this only works if ch is an int, so it can handle the value of -1 (EOF) and the byte 255 is not truncated to -1.
EDIT:
At first I said ch was 0 all the time. It was -1. I am so sorry, I swapped it with the null terminator, which is usually the reason for such behavior.
I've encountered a problem when validating a single-char scanf input in C and I cannot find an existing solution that works...
The scenario is: a method is taking a single letter 'char' type input and then validating this input, if the criteria is not met, then pops an error message and re-enter, otherwise return this character value.
my code is:
char GetStuff(void)
{
char c;
scanf("%c", &c);
while(c != 'A' || c != 'P')
{
printf("invalid input, enter again (A for AM or P for PM): ");
scanf ("%c", &dtChar);
}
return c;
}
however, i got the infinite loop of error message no matter what input I type in. I read some other posts and guess it's the problem that %c specifier does no automatically get rid of the newline when I hit enter, and so far I have tried:
putting a white space before/after %c like:
scanf(" %c", &c);
write a separate method or include in this GetStuff method to clean the newline like:
void cleanBuffer(){
int n;
while((n = getchar()) != EOF && n != '\n' );
}
Can anyone help me with this problem please? Thank you in advance.
Please consider the following snippet:
#include <stdio.h>
#include <ctype.h>
char GetStuff(void)
{
char c;
do {
printf("Please enter A for AM or P for PM: ");
scanf ("%c", &c);
// clean input buffer (till the end of line)
while(getchar()!='\n');
} while(toupper(c) != 'A' && toupper(c) != 'P');
return c;
}
int main(void)
{
printf("Your input is'%c'\n", GetStuff());
return 0;
}
Note the points:
condition while(c != 'A' || c != 'P') will be always true (just because one character cannot be 'A' and 'P' at the same time), so use while(c != 'A' && c != 'P') instead
No need for two scanf if you use do..while loop
After entering a char with scanf it is recommended to clean all characters from buffer, e.g. with while(getchar()!='\n'); (this will clean all input including incorrect and redundant characters)
use toupper to avoid making 4 comparison (actually single c=toupper(c) inside loop can minimize your while as while(c != 'A' && c != 'P') )
UPDATE:
To add message "Invalid input" and adding some other useful improvement subjected befor... new code is as:
#include <stdio.h>
#include <ctype.h>
void CleanBuffer(){
int n;
while((n = getchar()) != EOF && n != '\n' );
}
char GetStuff(void)
{
char c;
do {
printf("Please enter A for AM or P for PM: ");
scanf (" %c", &c);
c = toupper(c); // here letter become uppercase
CleanBuffer();
} while( (c != 'A' && c != 'P')?printf("Invalid input! "):0 );
return c;
}
int main(void)
{
printf("You have entered: %c\n", GetStuff());
return 0;
}
Note: function will return 'A' or 'P' in uppercase, so if this is not needed change the code as in example before update (use two toupper and do not change c after scanf). Also you can use tolower as an option (of course with comparing to 'a' and 'p').
#include <stdio.h>
char GetStuff(void) {
char c;
scanf("%c", &c);
getchar();
while ((c != 'A') && (c != 'a') && (c != 'P') && (c != 'p')) {
printf("invalid input, enter again (A for AM or P for PM): ");
scanf ("%c", &c);
getchar();
}
return c;
}
int main(void) {
printf("Calling GetStuff()...\n");
char x = GetStuff();
printf("User entered %c\n", x);
return 0;
}
You are using while (c != 'A' || c != 'P') as your loop conditional, but this will always return true. What you meant to use is the && "and" operator, instead of the || "or" operator.
Also, call getchar() after your scanf statements, to capture the newline. This should work the way you want it to.
Inside loop you are taking input in dtChar but your loop condition checks variable c which is not updated in the loop, that is causing infinite loop
Also you would change your condition
while(c != 'A' || c != 'P')
to
while(c != 'A' && c != 'P')
If you want user to enter either 'A' or 'P'
Another possible solution. As others mentioned the condition was to be done with &&. Anyway the big problem is how to remove what's left on the console input line. Since the console works by lines, we remove everything up to the next '\n'. If the user already left something on the input line before calling GetStuff(), it would be useful to add a call to SkipRestOfTheLine() before the while loop.
In general I suggest to start with a while(1) loop, before making it nicer (such as in the cleanBuffer() you posted).
#include <stdlib.h>
#include <stdio.h>
void SkipRestOfTheLine(void)
{
while (1) {
int c = fgetc(stdin);
if (c == EOF || c == '\n')
break;
}
}
char GetStuff(void)
{
while (1) {
int c = fgetc(stdin);
if (c == EOF)
exit(EXIT_FAILURE); // Deal with this case in an appropriate way
if (c == 'A' || c == 'P')
return c;
printf("invalid input, enter again (A for AM or P for PM): ");
SkipRestOfTheLine();
}
}
int main(void)
{
char c = GetStuff();
return 0;
}
try this,
char GetStuff(void)
{
char c;
scanf("%c", &c);
while (((c != 'A') || (c != 'a')) && ((c != 'P') || (c != 'p'))==1)
{
printf("invalid input, enter again (A for AM or P for PM): ");
scanf ("%c", &dtChar);
}
return c;
}
I hope this works, some time because of not given proper bracket it is stuck in the loop.
#include <stdio.h>
int main(){
char c;
do{
printf("invalid input, enter again (A for AM or P for PM): ");
scanf ("%s", &c);
}while ((c != 'A') && (c != 'P'));
return 0;
}
This is for homework . Must use only getchar and putchar
int main(void) {
int pch; //first
int ch; //second
while(1){
pch=getchar();
ch=getchar();
if(((pch>='A' && pch<='Z')) && ((ch>='A' && ch<='Z'))){
putchar(ch);
putchar(pch);
}
if((pch>='A' && pch<='Z') && ch=='\n') putchar(pch);
if(pch=='\n' || ch=='\n') break;
}
return EXIT_SUCCESS;
}
I need to swap chars using getchar and putchar . For exemple
PARIS
APIRS
And it works , but i need to hit ENTER two times when i even number of letters 4,6,8... . How do i eliminate this behavior ? Is there some way to kill \n for getchar
I typed PAR, hit one time enter and got APR. I believe this is what you want.
Is there some way to kill \n for getchar?
You need to do something like this:
char1 = getchar();
getchar(); // To kill `\n`
char2 = getchar();
getchar(); // To kill `\n`
Source.
Also as suggested by mch, you can do:
if(pch == '\n') break; after pch=getchar();
So you should change your program to this:
#include <stdio.h>
int main(void) {
int pch; //first
int ch; //second
while (1) {
pch = getchar();
if (pch == '\n') // when you hit enter once, break the loop
break;
ch = getchar();
if (((pch >= 'A' && pch <= 'Z')) && ((ch >= 'A' && ch <= 'Z'))) {
putchar(ch);
putchar(pch);
}
if ((pch >= 'A' && pch <= 'Z') && ch == '\n')
putchar(pch);
if (pch == '\n' || ch == '\n')
break;
}
return 0;
}
As part of my course, I have to learn C using Turbo C (unfortunately).
Our teacher asked us to make a piece of code that counts the number of characters, words and sentences in a paragraph (only using printf, getch() and a while loop.. he doesn't want us to use any other commands yet). Here is the code I wrote:
#include <stdio.h>
#include <conio.h>
void main(void)
{
clrscr();
int count = 0;
int words = 0;
int sentences = 0;
char ch;
while ((ch = getch()) != '\n')
{
printf("%c", ch);
while ((ch = getch()) != '.')
{
printf("%c", ch);
while ((ch = getch()) != ' ')
{
printf("%c", ch);
count++;
}
printf("%c", ch);
words++;
}
sentences++;
}
printf("The number of characters are %d", count);
printf("\nThe number of words are %d", words);
printf("\nThe number of sentences are %d", sentences);
getch();
}
It does work (counts the number of characters and words at least). However when I compile the code and check it out on the console window I can't get the program to stop running. It is supposed to end as soon as I input the enter key. Why is that?
Here you have the solution to your problem:
#include <stdio.h>
#include <conio.h>
void main(void)
{
clrscr();
int count = 0;
int words = 0;
int sentences = 0;
char ch;
ch = getch();
while (ch != '\n')
{
while (ch != '.' && ch != '\n')
{
while (ch != ' ' && ch != '\n' && ch != '.')
{
count++;
ch = getch();
printf("%c", ch);
}
words++;
while(ch == ' ') {
ch = getch();
printf("%c", ch);
}
}
sentences++;
while(ch == '.' && ch == ' ') {
ch = getch();
printf("%c", ch);
}
}
printf("The number of characters are %d", count);
printf("\nThe number of words are %d", words);
printf("\nThe number of sentences are %d", sentences);
getch();
}
The problem with your code is that the innermost while loop was consuming all the characters. Whenever you enter there and you type a dot or a newline it stays inside that loop because ch is different from a blank. However, when you exit from the innermost loop you risk to remain stuck at the second loop because ch will be a blank and so always different from '.' and '\n'. Since in my solution you only acquire a character in the innermost loop, in the other loops you need to "eat" the blank and the dot in order to go on with the other characters.
Checking these conditions in the two inner loops makes the code work.
Notice that I removed some of your prints.
Hope it helps.
Edit: I added the instructions to print what you type and a last check in the while loop after sentences++ to check the blank, otherwise it will count one word more.
int ch;
int flag;
while ((ch = getch()) != '\r'){
++count;
flag = 1;
while(flag && (ch == ' ' || ch == '.')){
++words;//no good E.g Contiguous space, Space at the beginning of the sentence
flag = 0;;
}
flag = 1;
while(flag && ch == '.'){
++sentences;
flag=0;
}
printf("%c", ch);
}
printf("\n");
I think the problem is because of your outer while loop's condition. It checks for a newline character '\n', as soon as it finds one the loop terminates. You can try to include your code in a while loop with the following condition
while((c=getchar())!=EOF)
this will stop taking input when the user presses Ctrl+z
Hope this helps..
You can implement with ease an if statement using while statement:
bool flag = true;
while(IF_COND && flag)
{
//DO SOMETHING
flag = false;
}
just plug it in a simple solution that uses if statements.
For example:
#include <stdio.h>
#include <conio.h>
void main(void)
{
int count = 0;
int words = 1;
int sentences = 1;
char ch;
bool if_flag;
while ((ch = getch()) != '\n')
{
count++;
if_flag = true;
while (ch==' ' && if_flag)
{
words++;
if_flag = false;
}
if_flag = true;
while (ch=='.' && if_flag)
{
sentences++;
if_flag = false;
}
}
printf("The number of characters are %d", count);
printf("\nThe number of words are %d", words);
printf("\nThe number of sentences are %d", sentences);
getch();
}
#include <stdio.h>
#include <ctype.h>
int main(void){
int sentence=0,characters =0,words =0,c=0,inside_word = 0,temp =0;
// while ((c = getchar()) != EOF)
while ((c = getchar()) != '\n') {
//a word is complete when we arrive at a space after we
// are inside a word or when we reach a full stop
while(c == '.'){
sentence++;
temp = c;
c = 0;
}
while (isalnum(c)) {
inside_word = 1;
characters++;
c =0;
}
while ((isspace(c) || temp == '.') && inside_word == 1){
words++;
inside_word = 0;
temp = 0;
c =0;
}
}
printf(" %d %d %d",characters,words,sentence);
return 0;
}
this should do it,
isalnum checks if the letter is alphanumeric, if its an alphabetical letter or a number, I dont expect random ascii characters in my sentences in this program.
isspace as the name says check for space
you need the ctype.h header for this. or you could add in
while(c == ' ') and whie((c>='a' && c<='z') || (c >= 'A' && c<='Z')
if you don't want to use isalpace and isalnum, your choice, but it will be less elegant :)
The trouble with your code is that you consume the characters in each of your loops.
a '\n' will be consumed either by the loop that scans for words of for sentences, so the outer loop will never see it.
Here is a possible solution to your problem:
int sentences = 0;
int words = 0;
int characters = 0;
int in_word = 0; // state of our parser
int ch;
do
{
int end_word = 1; // consider a word wil end by default
ch = getch();
characters++; // count characters
switch (ch)
{
case '.':
sentences++; // any dot is considered end of a sentence and a word
break;
case ' ': // a space is the end of a word
break;
default:
in_word = 1; // any non-space non-dot char is considered part of a word
end_word = 0; // cancel word ending
}
// handle word termination
if (in_word and end_word)
{
in_word = 0;
words++;
}
} while (ch != '\n');
A general approach to these parsing problems is to write a finite-state machine that will read one character at a time and react to all the possible transitions this character can trigger.
In this example, the machine has to remember if it is currently parsing a word, so that one new word is counted only the first time a terminating space or dot is encountered.
This piece of code uses a switch for concision. You can replace it with an if...else if sequence to please your teacher :).
If your teacher forced you to use only while loops, then your teacher has done a stupid thing. The equivalent code without other conditional expressions will be heavier, less understandable and redundant.
Since some people seem to think it's important, here is one possible solution:
int sentences = 0;
int words = 0;
int characters = 0;
int in_word = 0; // state of our parser
int ch;
// read initial character
ch = getch();
// do it with only while loops
while (ch != '\n')
{
// count characters
characters++;
// count words
while (in_word)
{
in_word = 0;
words++;
}
// skip spaces
while (ch == ' ')
{
ch = -1;
}
// detect sentences
while (ch == '.')
{
sentences++;
ch = -1;
}
// detect words
while ((ch != '\n')
{
word_detected = 1;
ch = -1;
}
// read next character
ch = getch();
}
Basically you can replace if (c== xxx) ... with while (c== xxx) { c = -1; ... }, which is an artifical, contrieved way of programming.
An exercise should not promote stupid ways of doing things, IMHO.
That's why I suspect you misunderstood what the teacher asked.
Obviously if you can use while loops you can also use if statements.
Trying to do this exercise with only while loops is futile and results in something that as little or nothing to do with real parser code.
All these solutions are incorrect. The only way you can solve this is by creating an AI program that uses Natural Language Processing which is not very easy to do.
Input:
"This is a paragraph about the Turing machine. Dr. Allan Turing invented the Turing Machine. It solved a problem that has a .1% change of being solved."
Checkout OpenNLP
https://sourceforge.net/projects/opennlp/
http://opennlp.apache.org/
Im writing a simple program to count the number of character user is entered, and i wrote an if to check wether there is a newline but still printing it..
the code:
#include <stdio.h>
int main()
{
char ch;
int numberOfCharacters = 0;
printf("please enter a word, and ctrl + d to see the resault\n");
while ((ch = getchar()) != EOF)
{
if (numberOfCharacters != '\n')
{
numberOfCharacters++;
}
}
printf("The number of characters is %d", numberOfCharacters);
return 0;
}
what am i doing wrong?
Think about this line:
if (numberOfCharacters != '\n')
how can it make sense? You are comparing the number of characters read so far with a newline, it's like comparing apples to oranges and surely won't work. It's another variable that you should check...
Change your loop to this.
while ((ch = getchar()) != EOF)
{
if(ch != '\n')
numberOfCharacters++;
}