Rename or/and Change location of a file in C

#include <cstdio>
using namespace std;
int main()
{
    char oldname[] = "ab.txt";
    char newname[] = "as.txt";

    if (rename(oldname, newname) != 0)
        perror("Error renaming file");
    else
        printf("File renamed successfully");

    return 0;
}