string manipulate

I want to take all of a specific letter from a string and insert another letter were the old ones were i just cant figure out how.For example say you enter the string "goodbye" and i want to change all the o's to a's how would i do that?

Loop over the characters of the string. Whenever the current character is an 'o', assign an 'a'.

Here's an example:

Code:

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#include <stdio.h>
#include <string.h>

int main(void)
{
        char str[] = "goodbye";
        int str_len = strlen(str);
        int x;

        printf("BEFORE: %s\n", str);

        for(x = 0; x < str_len; x++)
        {
                if(str[x] == 'o')
                        str[x] = 'a';
        }
               
        printf("AFTER: %s\n", str);
       
        return 0;       
}

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Another way to loop over a string using the fact that c strings are Null terminated:

Code:

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for (i = 0;str[i] != '\0';++i) ;

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And it retains the "spirit of the language" which strlen() does not.