JavaScript中输入的数字如何相加？

Question

因此，我的代码允许用户输入 2 个数字，num1 和 num2。但是，加法函数是连接数字而不是相加。请问我该如何解决这个问题？

这是函数的一个片段：

var sum= num1 + num2;
alert(`Sum of ${num1} and ${num2} is ${sum}`);

Answer 1

value 的类型为 string。这就是字符串连接发生的原因。要执行算术运算，您必须将值转换为数字。

改变

var sum= num1 + num2;

到

var sum= Number(num1) + Number(num2);

Answer 2

你需要将字符串转换为数字，+符号是连接字符串，这里是例子

var sum= Number(num1) + Number(num2);
alert(`Sum of ${num1} and ${num2} is ${sum}`); // Sum of 1 and 2 is 3

或

var sum= +num1 + +num2;
alert(`Sum of ${num1} and ${num2} is ${sum}`); // Sum of 1 and 2 is 3

Answer 3

这是因为即使输入类型是数字，值也是字符串形式，而不是添加它，它会在添加之前将 values.Convert 它们连接到数字

var sum = Number(num1) + Number(num2);
alert(`Sum of ${num1} and ${num2} is ${sum}`);

Answer 4

您可以强制将其串起来并使用 "" + num1 + num2

var sum = "" + num1 + num2;
alert('Sum of ${num1} and ${num2} is ${sum}');

Answer 5

另一个想法是使用 parseInt()

const sum = parseInt(num1) + parseInt(num2)
console.log(`Sum of ${num1} and ${num2} is ${sum}`)

这里是工作代码

let num1 = 50
let num2 = "5" //in case of string value the value will be converted by parseInt()
const sum = parseInt(num1) + parseInt(num2)
console.log(`Sum of ${num1} and ${num2} is ${sum}`)

JavaScript中输入的数字如何相加？

How do I add numbers that have been inputted in JavaScript?

javascript

addition