java中ParseInt收到的int和int之间的区别 [英] Difference between int and int received by ParseInt in java

问题描述

int i = 0;
int k = Integer.parseInt("12");
int j = k;
System.out.println(i+1 + " " + j+1);

奇怪的是收到的输出是

1 121

我无法弄清楚这个基本区别。请帮助我。

I can not figure out this basic difference. Please help me.

推荐答案

使用括号如下

System.out.println((i+1) + " " + (j+1));

来自 docs

+运算符在语法上是左关联的，无论后来由类型分析确定
来表示字符串连接
或加法。在某些情况下，需要注意获得所需的结果。
例如，表达式：

The + operator is syntactically left-associative, no matter whether it is later determined by type analysis to represent string concatenation or addition. In some cases care is required to get the desired result. For example, the expression:

a + b + c始终被视为含义：（a + b）+ c

a + b + c is always regarded as meaning: (a + b) + c

将此扩展到您的场景

i+1 + " " + j+1

它变为

(((i + 1) + " ") + j)+1

由于 i 是一个int所以（i + 1）= 1 ，简单的加法

Since i is an int so (i + 1) = 1 , simple addition

是字符串因此（（i + 1）+） = 1 WITH SPACE （String 连接）

" " is a String hence ((i + 1) + " ") = 1 WITH SPACE (String concatenation)

类似地，当 j 并且最后 1 已添加，它被添加到字符串因此字符串 连接发生，这证明你得到的输出是合理的。

Similarly when j and last 1 is added, its being added to a String hence String concatenation takes place, which justifies the output that you are getting.

参见

• JLS 15.18.1字符串连接运算符+

• JLS 15.18.1 String Concatenation Operator +

这篇关于java中ParseInt收到的int和int之间的区别的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！