Rename.c

#include <stdio.h>

int main() {
  char old_name[] = "geeks.txt";

  char new_name[] = "geeksforgeeks.txt";
  int value;

  value = rename(old_name, new_name);

  if (!value) {
    printf("%s", "File name changed successfully");
  } else {
    perror("Error");
  }
  return 0;
}