#include<stdio.h>
#include<stdlib.h>

int length(char *str)
{
    int len = 0;
    while(str[len++] != '\0');
    return len - 1;
}

char *concatenate(char *str1, char *str2)
{
    int len1 = length(str1), len2 = length(str2);
    char *retval = (char *)malloc(sizeof(char) * (len1 + len2 + 1));
    for(int i = 0; i < len1 + len2 + 1; i++)
        retval[i] = i < len1 ? str1[i] : (i < len1 + len2 ? str2[i - len1] : '\0');
    return retval;
}

int main()
{
    char meme[] = "meme";
    char review[] = "review";
    printf("%s %d, %s %d\n", meme, length(meme), review, length(review));
    char *memeReview = concatenate(meme, review);
    printf("%s %d\n", memeReview, length(memeReview));
    return 0;
}