Reverse a String In-Place

Code

#include <stdio.h>

void reverse_string(char *str) {
    int i = 0;
    while(*(str+i)!='\0')
        i++;
    for(int j = 0; j < i/2; j++){
        *(str+j) ^= *(str+ i - j -1);
        *(str+ i - j -1)  ^= *(str+j);
        *(str+j) ^= *(str+ i - j -1);
    }
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    int i = 0;
    while (str[i] != '\0') {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    reverse_string(str);
    printf("%s", str);
    return 0;
}

Solving Approach

 

 

 

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Input

firmware

Expected Output

erawmrif