Thread: How do I replace two a's in a string with an '*' unknown input length

Hey guys so for my assignment I have to replace two a's with an '*' from a string of unknown input length in C. The challenge is I am only allowed to use the getchar() and the putchar() function.
With an array it would have been easier but I am not even allowed to use that.

This is what I have tried

But it replaces all the a's with '*'.

Code:

#include <stdio.h>

int ch;

int main()
{
    while ((ch = getchar()) !=EOF && ch != '\n'  ) { 
        if(ch=='a'){
            if(ch=='a'){
                ch='*';
            }
        }
        putchar(ch);
    }
    putchar('\n');
    return 0;
}

Could someone just guide me to the correct path or just tell me which approach I should take?



Thank you in advance.