由题意可知,需要从控制台接收一个字符,判断其是否为小写字母或者大写字母,然后大小写转换输出
import java.util.Scanner;
public class Change{
public static void main(String[] args){
Scanner scanner = new Scanner(System.in);
// 用于接收单个字符
char c = scanner.next().charAt(0);
if('a'<=c && c <= 'z'){
System.out.println((char)(c - 32));
}else if ('A' <= c && c <= 'Z'){
System.out.println((char)(c + 32));
}else {
System.out.println("你输入了错误的字母!");
}
}
}