刚开始学Java，这个输出是输出一个然后换行，这样写为什么不行呢

Question

public class hellow {
    public static void main(String[] args) {
        int id=104;
        char sex='M';
        String str="aaa";
        short grade=1;
        int age=19;
        double num=900;
        float j=399;
        boolean boo=false;
        long pc=299625l;
        System.out.println(id'\n'sex'\n'str'\n'grade'\n'grade'\n'age'\n'num'\n'j'\n'boo'\n'pc);
    }
}

Answer 1

System.out.println()里的参数应为变量或是表达式

id'\n'sex'\n'str'\n'grade'\n'grade'\n'age'\n'num'\n'j'\n'boo'\n'pc这一长串电脑无法作为表达式或变量去识别

可以用+号连接每一个变量、表达式与字符串，并在最前加入""+确保所有的变量和表达式转化为字符串，如下

System.out.println(""+id+'\n'+sex+'\n'+str+'\n'+grade+
    '\n'+grade+'\n'+age+'\n'+num+'\n'+j+'\n'+boo+'\n'+pc);