i am trying to convert characters in a string from capital letter to small letter using for loop.it&-CodePudding

i cannot find any error in the code

#include <stdio.h>
#include <stdlib.h>

int main(void) {

    char a[50];
    int i;

    setbuf(stdout,NULL);

    printf("enter a string");

    gets(a);

    for(i=0;a[i]<='\0';i  ){
        if(a[i]>='A'&&a[i]<='Z'){
            a[i]=a[i] 32;
        }
    }

    printf("%s",a);

    return EXIT_SUCCESS;
}

output

enter a string SDJnjj SDJnjj

CodePudding user response：

Your whole for loop is skipped, character '\0' is zero, any printable string you enter won't have characters less than zero. Instead, change the condition to !=:

for(i=0; a[i]!='\0'; i  ){ ... }

or simply a[i] since 0 evaluates to false in C

for(i=0; a[i]; i  ){ ... }

Also, never use gets, it creates a security vulnerability for buffer overflows, use fgets instead.

Furthermore, there's already a function that does this for you called tolower. It is the preferred method if you're allowed to use it:

#include <ctype.h>
...

for(i=0;a[i];i  ){
    a[i]=tolower(a[i]);
}