program to understand rename() function

using codeblocks
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//understanding rename() function
#include <stdio.h>
#include<conio.h>

int main()
{
  char first_name[40],second_name[40];

  printf("enter file name with extension .txt\n");
  gets(first_name);
  printf("enter name to be changed\n");
  gets(second_name);
    rename("first_name","second_name");
    printf("the entered file renamed successfully");
    getch();
    return 0;
}

//note: We do not need to open file here. We can do without opening too(from line 19).
/*i.e
//understanding rename() function
#include <stdio.h>
#include<conio.h>
int main()
{
  char first_name[40],second_name[50];
  printf("enter file name with extension .txt\n");
  gets(first_name);
    printf("enter name to be changed\n");
    gets(second_name);
    rename("first_name","second_name");
    printf("the entered file renamed successfully");
    getch();
    return 0;
}
*/

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same program, we can use for turboc++ as well