C programming language files topic (c)

1. From the keypad to enter a string, all lowercase letters to uppercase letters, and then output to a disk file "test" to save.
Enter a string! End

#include<stdio.h>
#include<stdlib.h>
int main() {
	char ch;
	FILE *fp;
	fp = fopen("E:\\test.txt","w");
	if(!fp) {
		printf("文件不存在");
		exit(0);
	}
	printf("请输入一个字符串并且以！结束:\n");
	ch = getchar();
	while(ch != '!') {
		if(ch >='a' && ch <= 'z') {//小写字母转大写字母 
			ch-=32;
		}
		fputc(ch,fp);
		putchar(ch);                  // 将输出的字符显示在屏幕上
		ch=getchar();                 // 再接收从键盘输入的一个字符（不加这句话会出现死循环）
	}
	fclose(fp);
}

 

【operation result】

(1) In the console displays the results

(2) results in the input file