include <stdio.h>

int main()
{
char ch;
printf("请输入一个字母");
scanf_s("%c", &ch);
if ('A' <= ch && ch <= 'Z');
{
printf("%d\n", ch);
}
else if ('a' <= ch && ch <= 'z');
{
printf("%c\n", ch - 32);

}
return 0;

}

回答

#include <stdio.h>
int main(){
  char ch;
  printf("请输入一个字母");
  scanf("%c", &ch);
  if ('A' <= ch && ch <= 'Z'){
    printf("%d\n", ch);
  }
  else if ('a' <= ch && ch <= 'z'){
    printf("%c\n", ch - 32);
  }
  return 0;
}