给文件或者文件夹改名

比如把  E:\正则.txt 改成 E:\正则.c

#include <stdio.h> 

int main(void) 
{ 
   char oldname[80], newname[80]; 

   /* prompt for file to rename and new name */ 
   printf("File to rename: "); 
   gets(oldname); 
   printf("New name: "); 
   gets(newname); 

   /* Rename the file */ 
   if (rename(oldname, newname) == 0) 
      printf("Renamed %s to %s.\n", oldname, newname); 
   else 
      perror("rename"); 

   return 0; 
}