C语言实现大小写字母转换

#include 
#include 

int main(){
	char ch = 0;
	//ch = getchar();
	while ((ch=getchar()) != EOF){
		if ((ch>='a') && (ch<='z')){
			//ch = ch - 32;
			ch = ch - ('a'-'A');
			printf("ch=%c\n", ch);
		}
		else if ((ch>='A') && (ch<='Z')){
			//ch = ch + 32;
			ch = ch + ('a'-'A');
			printf("ch=%c\n", ch);
		}
	}

	return 0;
}

输出结果：