#include 
#include 

using namespace std;

int main()
{
    char oldname[] = "file_old.txt";
    char newname[] = "file_new.txt";
    
    /*    Deletes the file if exists */
    if (rename(oldname, newname) != 0)
        perror("Error renaming file");
    else
        cout << "File renamed successfully";
    
    return 0;
}