Why can't my code detect the space in ' '?

user_19570757 0
Viewed 79

I'm new to C/C++ and I'm doing this exercise in my course that requires a while loop, and this code supposedly counts characters without spaces. I'm really confused why this counts the spaces as well, because I used a similar syntax with fgets instead of getchar and it worked fine.

int main()
{
    //method 2
    char str[100];
    int i = 0;
    char c;
    int count2 = 0;
    
    printf("Enter characters.\n");
    while (c = getchar() != '\n') {
        if (c != ' ') {
            count2++;
        }
    }
    printf("There are %d characters\n", count2);
    return 0;
}
c
2 Answers
#include <stdio.h>
int main(){

    int i = 0;
    char c;
    int count2=0;
    printf("Enter characters.\n");
    c=getchar();
    while (c!='\n')
    {
        if (c != ' ')
        {
            count2++;
        }
        c=getchar();
    }
    printf("There are %d characters\n", count2);
    return 0;
}

This is the right version. It seems that the check in the cycle try to do getchar()!='\n' and after the assignment of the value to the variable c

user_69409220

There are multiple problems in your code:

  • you must include <stdio.h> to call getchar and printf

  • the test while (c = getchar() != '\n') is parsed as c = (getchar() != '\n'): c gets the value 1 for all bytes except the newline, hence all bytes in the line are counted.

    You should instead write:

      while ((c = getchar()) != '\n') ...

  • the while loop never stops if the file does not contain a newline. You should also test for EOF:

      while ((c = getchar()) != EOF && c != '\n') ...

  • to properly test for EOF, you must define c with type int.

Here is a modified version:

#include <stdio.h>

int main() {
    //method 2
    int c, count2;
    
    printf("Enter characters.\n");
    count2 = 0;
    while ((c = getchar()) != EOF && c != '\n') {
        if (c != ' ') {
            count2++;
        }
    }
    printf("There are %d characters\n", count2);
    return 0;
}
user_45932670
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