Ucitavanje dva niza i spajanje njih, zatim okretanje istog i ispis njega

string-merge-reverse.c

/*
* Compiled using GCC 5.1
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

//preprocessor
void reverse(char s[], int s3l){
    char r[s3l];
    int c, d;
    for (c = s3l - 1, d = 0; c >= 0; c--, d++)r[d] = s[c];
    r[d] = '\0';
    printf("Reversed string3 je %s",r);
}

int main(){
    printf("Unesite maksimalnu duzina nizova: ");
    int n=0;
    scanf("%d",&n);
    char string1[n], string2[n], string3[2*n];
    printf("Unesite string1: ");
    scanf("%s",string1);
    puts("");
    printf("Unesite string2: ");
    scanf("%s",string2);
    strncpy(string3,string1,sizeof(string1));
    char *sp;
    sp = &string3[strlen(string1)];
    strncpy(sp,string2,sizeof(string2));
    printf("string3 is %s\n",string3);
    int s3l = strlen(string3);
    reverse(string3,s3l);
    return 0;
}