mcqjsday1

Author: nilajcoder

JavaScript Interview/Most Imp MCQ/chatgpt.js

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+/*-
+function a() {
+    var b=10;
+    c();
+    function c() {
+        console.log(b);
+        
+    }
+    
+}
+a();
+
+// Output: 10
+*/
+/*
+2.WAP In JS to print 1 to 5 with 1 sec interval then 2 then 3 so on using setTimeout  and closure
+
+function x(){
+    for(let i=1; i<=5; i++){
+        setTimeout(function(){
+            console.log(i);
+        },i* 1000);
+    }
+}
+x();// Output: 1 2 3 4 5
+
+*/
+
+/*
+3
+function x(){
+    for(var i=1; i<=5; i++){
+        function closer(x){
+            setTimeout(function(){
+                console.log(x);
+            },x* 1000);
+
+        }
+        closer(i);
+       
+    }
+}
+x();
+// Output: 1 2 3 4 5
+
+
+4. wAP to find area of circle using function and array
+
+const radius =[5,6,7,8,9];
+const area = function(radius){
+    const Output =[];
+    for(let i=0; i<radius.length; i++){
+        Output.push(Math.PI*radius[i]*radius[i]);
+    }
+    return Output;
+}
+
+console.log(area(radius));
+
+What is Higher order function?
+ans: A higher-order function is a function that takes
+ one or more functions as arguments, returns a function as its result,
+  or both. In other words, it can operate on functions, either by taking them as parameters or by returning them.
+
+5. Higher order function to find area, circumference and diameter of circle using function and array
+const radius =[5,6,7,8,9];
+
+const area = function(radius){
+    
+    return Math.PI*radius*radius;
+};
+
+const circumference = function(radius){
+        
+        return 2*Math.PI*radius;
+    };
+
+const diameter = function(radius){
+            
+            return 2*radius;
+ }
+
+const calculate = function(radius, logic){
+    const Output =[];
+    for(let i=0; i<radius.length; i++){
+        Output.push(logic(radius[i]));
+    }
+    return Output;
+}
+
+console.log(calculate(radius, area));
+console.log(calculate(radius, circumference));
+console.log(calculate(radius, diameter));
+
+
+6. Map 
+
+const r=[5,6,7,8,9];
+const Double = function(x){
+    return 2*x;
+};
+
+function Square(x){
+    return x*x;
+}
+
+function Cube(x){
+    return x*x*x;
+}
+
+function SquareRoot(x){
+    return Math.sqrt(x);
+}
+function Binary(x){
+    return x.toString(2);
+}
+
+const Output=r.map(Double)
+const Output1=r.map(Binary)
+console.log(Output1);
+console.log(Output);
+
+7. Filter
+
+const r=[5,6,7,8,9];
+
+function isOdd(x){
+    return x%2!==0;
+}
+function isEven(x){
+    return x%2===0;
+}
+
+function isPrime(x){
+    if(x<2) return false;
+    for(let i=2; i<=Math.sqrt(x); i++){
+        if(x%i===0) return false;
+    }
+    return true;
+}
+function isPerfectSquare(x){
+    return Number.isInteger(Math.sqrt(x));
+}
+function isArmstrong(x){
+    const str = x.toString();
+    const len = str.length;
+    let sum = 0;
+    for(let i=0; i<len; i++){
+        sum += Math.pow(Number(str[i]), len);
+    }
+    return sum === x;
+}
+
+const Output=r.filter(isOdd)
+const Output1=r.filter(isEven)
+console.log(Output1);
+console.log(Output);
+
+8. Reduce
+
+const r=[5,5,5,5,5];
+
+function sumofall(x){
+    let sum = 0;
+    for(let i=0; i<x.length; i++){
+        sum += x[i];
+    }
+    return sum;
+}
+
+const Output=r.reduce((acc, curr) => acc + curr, 0);
+
+console.log(Output);
+*/
+
+
+
+// Four Example of falsy values in JS
+/*
+// 1. undefined
+var a;
+console.log(typeof(a));// undefined
+console.log(Boolean(a));
+// 2. null
+var a = null;
+console.log(typeof(a));// object
+console.log(Boolean(a));// false
+
+
+// 3. NaN
+var a = NaN;
+console.log(typeof(a));
+console.log(Boolean(a));
+// 4. 0
+var a = 0;
+console.log(typeof(a));// number
+console.log(Boolean(a));// false
+*/
+/*
+// 5. "" (empty string)
+var a = "";
+console.log(typeof(a));// string
+console.log(Boolean(a));// false
+*/
+
+/*
+let b;
+console.log(b);// undefined
+
+*/
+
+
+/*
+var a;
+console.log(a);// undefined
+
+*/
+/*
+const a;
+console.log(a);// SyntaxError: Missing initializer in const declaration
+
+*/
+
+
+/*
+console.log(a); // ReferenceError: Cannot access 'a' before initialization
+let a = 10;
+*/
+
+/*
+console.log(a); // undefined
+var a; // undefined
+*/
+
+/*
+console.log(a); // ReferenceError: Cannot access 'a' before initialization
+const a;
+*/
+
+/*
+console.log(name);// undefined
+var name;
+*/
+
+/*
+function sum(a, b) {
+    return a + b;
+}
+
+console.log(sum(2, 3)); // 5*
+*/
+
+/* Lambda function or Arrow function  Example give the output of 1 to 5
+  
+  What is Lambda function or Arrow function?
+    ans: An arrow function is a shorter syntax for writing function expressions in JavaScript.
+          example: const add = (a, b) => a + b;
+            It is a more concise way to write functions, especially when using them as arguments to higher-order functions.
+            what is expression?
+            ans: An expression is a piece of code that produces a value. It can be a variable, a function call, or an operation that evaluates to a value.
+
+
+const numbers = [1, 2, 3, 4, 5];
+const squares = numbers.map(num => num * num);
+console.log(squares); // Output: [1, 4, 9, 16, 25]
+
+
+
+function sum(...num){
+    return num.reduce((a,b)=>a+b,0)
+}
+
+console.log(sum(1,2))
+console.log(sum(1,2,3))
+console.log(sum(1,2,3,4))
+
+
+console.log(typeof null);//object
+
+
+  let a = 5;
+let b = "5";
+console.log(a == b); //true
+console.log(a === b); //false
+
+
+console.log(0.1 + 0.2 === 0.3); //false
+
+
+console.log([] == []);//false
+
+console.log(typeof NaN); //number
+
+let x;
+console.log(x + 2); //NAN
+
+
+let x;
+console.log(x - 2); //NAN
+
+
+
+let x;
+console.log(x * 2); //NAN
+
+
+let x;
+console.log(x / 2); //NAN
+
+
+console.log("5" - 2); //3 number
+console.log("5" + 2); //52 string
+
+console.log(typeof typeof 1);//string   typeof number  number is string
+
+console.log(typeof typeof 10.25);//string   
+
+console.log(typeof typeof null);//string   
+
+console.log(typeof typeof undefined);//string   
+
+
+console.log( typeof typeof Infinity);//string   
+
+console.log(typeof Object);//function
+
+
+console.log(typeof typeof true);//string
+
+console.log(3 > 2 > 1); //false   true>1   type coreceion false
+
+let a = [1, 2, 3];
+let b = a;
+b.push(4);
+console.log(a);//[1,2,3,4]
+*/
+
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