题解 | #字母大小写转换#

#include <stdio.h>

int main(){
    char ch;
    while(scanf("%c",&ch)!=EOF){
        getchar();
        if(isupper(ch)){
            printf("%c\n",ch+32);
        }
        if(islower(ch)){
            printf("%c\n",ch-32);
        }
    }
    return 0;
}