当“+”操作中出现字符串时,这个”+”是字符串连接符。而不是算术运算
public class HelloWorld{
public static void main(String[] args) {
System.out.println("today"+" nice"); //输出 today nice
System.out.println(666+" nice"); //输出 666 nice
System.out.println(1 + 99 + " nice"); //输出 100 nice
System.out.println("nice " + 1 + 99); //输出 nice 199
}
}