#include<stdio.h>
int main()
{   char c1,c2;
    printf("请输入一个字符:");
    c1=getchar();
    if(c1>='a'&&c1<='z')
       c2=c1-32;
    else if(c1>='A'&&c1<='Z')
	   c2=c1+32;
	else
	   c2=c1+1;
	putchar(c2);
	return 0;
}