how to check if number is integer code example

Example 1: integer check in javascript

var a=Number.isInteger(5); //True
var b= Number.isInteger(01); //True
var c=Number.isInteger("10"); //False

console.log(a,b,c);  //true true false

Example 2: javascript check if number

function isNumber(n) { return /^-?[\d.]+(?:e-?\d+)?$/.test(n); } 

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isNumber('123'); // true  
isNumber('123abc'); // false  
isNumber(5); // true  
isNumber('q345'); // false
isNumber(null); // false
isNumber(undefined); // false
isNumber(false); // false
isNumber('   '); // false

Example 3: how to check if number is integer in java

if(x == (int)x){
 println("x is an integer");
}

Example 4: algorithm to know if a number is an integer

// The most basic thing you could do is check if x=floor(x).
  
  if (num != Math.floor(num)) { ... }