程序代码：

#include<stdio.h>
main()
{
FILE *fp;
if((fp=fopen("text.txt","w"))==NULL)
puts("Error on opening output file text");

char ch;
while((ch=getchar())!=EOF&&ch!='!')//输入字符串改成以字符输入
{
    if(ch>='a'&&ch<='z')
        ch=ch-32;
    fputc(ch,fp);
}
return 0;
fclose(fp);
}