Jshell无法使用println方法正确打印

Question

当使用无括号时，为什么Jshell将r，s视为字符串？

PS C:\Users\saiko\OneDrive\Learning\java> Jshell                                                                                                                                             
|  Welcome to JShell -- Version 11.0.6
|  For an introduction type: /help intro

jshell> int p = 10;  int q =20; int r=5; int s=10;
p ==> 10
q ==> 20
r ==> 5
s ==> 10

jshell> if( (p+q) > (r+s) ) System.out.println( p+q+" is greater than  "+r+s );
30 is greater than  510

jshell> if( (p+q) > (r+s) ) System.out.println( (p+q) +" is greater than  "+ (r+s) );
30 is greater than  15

jshell>

Answer 1

正如评论和Java tutorials中所说的那样

从左到右计算除赋值运算符以外的所有二元运算符

在表达式p+q+" is greater than "+r+s中，第一个求值是p+q results In int，然后是p+q+" is greater than " results in String，所有后续求值结果也是String。

这就是为什么你会获得：

30 is greater than  510