这个程序哪里错了？文件修改
#include<stdio.h>#include<stdlib.h>
void main()
{FILE *fp1,*fp2;
char ch1,ch2;
fp1=fopen("C:\\String.txt","r+");
fp2=fp1;
while((ch1=fgetc(fp1))!=EOF);
{if('a'<=ch1&&ch1<='z')ch2=ch1-32;
else if('A'<=ch1&&ch1<='Z')ch2=ch1+32;
else ch2=ch1;
fputc(ch2,fp2);}
fclose(fp2);
fclose(fp1);
}
