题解 | #大小写转换#

#include <stdio.h>

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