How to implement arithmetic addition in javascript

Javascript method to implement arithmetic addition: 1. Use the " " operator, syntax "a b"; 2. Use the "=" operator, syntax "a = b"; 3. Use " " increment operation symbol, syntax "a" or "a".

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

How to implement addition operation in javascript

Method 1: Use the " " operator

Example 1: Pay attention to the summation operation of special operands

var n = 5;  //定义并初始化任意一个数值
console.log(NaN + n);  //NaN与任意操作数相加，结果都是NaN
console.log(Infinity + n);  //Infinity与任意操作数相加，结果都是Infinity
console.log(Infinity + Infinity);  //Infinity与Infinity相加，结果是Infinity
console.log((-Infinity) + (-Infinity));  //负Infinity相加，结果是负Infinity
console.log((-Infinity) + Infinity);  //正负Infinity相加，结果是NaN

Example 2: The addition operator can determine whether it is an addition operation or a connection operation based on the data type of the operands

console.log(1 + 1);  //如果操作数都是数值，则进行相加运算
console.log(1 + "1");  //如果操作数中有一个是字符串，则进行相连运算
console.log(3.0 + 4.3 + "");  //先求和，再连接，返回"7.3"
console.log(3.0 + "" + 4.3);  //先连接，再连接，返回"34.3"
                              //3.0转换为字符串3

Note: In When using the addition operator, you should first check whether the data type of the operand meets the requirements.

Method 2: Use the "=" operator

The role of the "=" operator: perform an addition operation or connection operation on the right operand before assigning a value, Then copy the operation result to the left operand

var a=1,b=2,c=3,d=4;
console.log(a+=b);
console.log(b+=a);
console.log(c+=b);
console.log(d+=d);
console.log(a);
console.log(b);
console.log(c);
console.log(d);

Method 3: Use the " " increment operator

Increment Operation is a simple way to change its own result by continuously adding 1 and then assigning the result to the left operand.

As a unary operator, the increment operator functions on variables, array elements or object properties, and cannot act on direct quantities. According to different positions, it can be divided into 2 operation methods:

• Prefix increment (n): increment first and then assign value.

• Post-increment (n): assign value first, then increment.

Example:

var a = b = c = 4;
console.log(a++);  //返回4，先赋值，再递增运算结果不变
console.log(++b);  //返回5，先递增，再赋值，运算结果加1
console.log(c++);  //返回4，先赋值，再递增，运算结果不变
console.log(c);  //返回5，变量的值加1
console.log(++c);  //返回6，先递增，再赋值，运算结果加1
console.log(c);  //返回6

[Recommended learning: javascript advanced tutorial]

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