int main(void)
{
char ch1;
scanf("%c",&ch1);
if (ch1 >= ‘A’ && ch1 <= ‘Z’)
{
ch1+=32;
printf("%cn",ch1);
}
else if(ch1 >= ‘a’ && ch1 <= ‘z’)
printf(“您输入的不是大写字母!”);
else
printf(“您输入的不是字母!”);
return 0;
}

int main(void)
{
char ch1;
scanf("%c",&ch1);
if (ch1 >= ‘A’ && ch1 <= ‘Z’)
{
ch1+=32;
printf("%cn",ch1);
}
else if(ch1 >= ‘a’ && ch1 <= ‘z’)
printf(“您输入的不是大写字母!”);
else
printf(“您输入的不是字母!”);
return 0;
}