题解 | #字母大小写转换#

#include <ctype.h>

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