String Functions

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

void reverseString(char s[]) {
    int i = 0, j = strlen(s) - 1;
    while (i < j) {
        char temp = s[i];
        s[i] = s[j];
        s[j] = temp;
        i++;
        j--;
    }
}

void toUpperCase(char s[]) {
    for (int i = 0; s[i] != '\0'; i++) {
        s[i] = toupper((unsigned char)s[i]);
    }
}

int main() {
    char s1[80] = "Namaste";
    char s2[80] = "Duniya";
    char rev[80] = "Code";
    char up[80] = "codingeasily";

    printf("Length = %d\n", (int)strlen(s1));
    strcat(s1, " ");
    strcat(s1, s2);
    printf("Joined = %s\n", s1);
    printf("Compare = %d\n", strcmp("abc", "abc"));

    reverseString(rev);
    printf("Reverse = %s\n", rev);

    toUpperCase(up);
    printf("Uppercase = %s\n", up);
    return 0;
}