#include <stdio.h>

void reverse(char stringp[]);
void reverse2(char string[]);
void reverse3(char* string);
int stringSize(char string[]);

int main(void) {
    char string[] = "Reverse me";

    printf("%s\n", string);
    reverse(string);
    printf("%s\n", string);
    reverse2(string);
    printf("%s\n", string);
    reverse3(string);
    printf("%s\n", string);
}

void reverse(char string[]) {
    int size, i, j;

    size = stringSize(string);

    // reverse
    for(i = 0, j = size - 1; i <= j; i++, j--) {
        char temp = string[j];
        string[j] = string[i];
        string[i] = temp;
    }
}

void reverse2(char string[]) {
    int i, size;

    size = stringSize(string);

    for(i = 0; i != size / 2; i++) {
        char temp = string[size - i - 1];
        string[size - i - 1] = string[i];
        string[i] = temp;
    }
}

void reverse3(char* string) {
    int i, size;

    size = stringSize(string);

    for(i = 0; i != size / 2; i++) {
        char temp = string[(size - i - 1) * sizeof(char)];
        string[(size - i - 1) * sizeof(char)] = string[i * sizeof(char)];
        string[i * sizeof(char)] = temp;
    }
}

int stringSize(char string[]) {
    int size;

    for(size = 0; string[size] != '\0'; size++)
        ;

    return size;
}