c读取文件名可变: 1#include<stdio.h>2#include<string.h>3#include<windows.h>4#include5#definemaxn 506#defineNSIZE 87charfilename[50];8intmain()9{10FILE *fp=NULL;11printf("输入文件名:\n");12scanf("%s",filename);13strcat(filename,".txt");14fp=fopen(filename,"w");15fprintf(fp,...