:---- Control Statement & Loops :----
If..Else
Switch Statement
While Loop
Do-While Loop
For Loop
For in Loop
For of Loop
Conditional (ternary) operator
1. If else :-
The if statement executes a statement if a specified condition is truthy.
If the condition is falsy, another statement can be executed.
var tommorow = "sunny";
if(tommorow=="rain"){
console.log("take an umberalla");
}else{
console.log("No need to take an umberalla")
}
var area = "triangle";
var PI = 3.14;
var l = 5;
var b = 4;
var r = 3;
if(area =="circle"){
console.log(PI*r**2);
}else if(area == "triangle"){
console.log(l*b/2);
}else if(area == "rectangle"){
console.log(l*b);
}else{
console.log("Please enter valid Data");
}
Question :- what is truthy and falsy value in JavaScript .
We have total 5 falsy value in javaScript
0 , "" , undefined , null , NaN , false
if (true) {
console.log("We Loss the game");
}else{
console.log("We won the game");
}
2. Conditional (ternary) operator
The conditional (ternary) operator is the only JavaScript
Operator that takes three operands.
This is Short Hand of If else
var age = 31;
console.log((age>=18) ? "you can vote" : "You can't vote") ;
3. Switch Statement :-
Evalutates an expression , matching the expression's value to
a case clause, and executes statements associated with the case.
var area = "triangle";
var PI = 3.14; l = 5; b = 4; r = 3;
switch(area){
case "circle":
console.log("The area of circle is " + PI*r**2)
break;
case "triangle":
console.log("The area of triangle is " + l*b/2);
break;
case "rectangle":
console.log("The area of rectangle is " + l*b);
break;
default:
console.log("Please enter Valid Data");
}
break
Terminates the current loop, switch or label
statement and transfers
Program control the statement following the terminated statement.
4. While Loop Statement :-
The while Statement creates the loop that execute a specified statement
as long as the test condition evaluates to true.
var num=0;
while (num<=100) {
console.log(num); // infinite Loop
num++;
}
5. Do-While Loop Statement :-
var num = 0;
do {
console.log(num);
num++;
} while (num<=10);
6. For Loop Statement :-
for(var num = 0; num<=10 ; num++){
console.log(num);
}
Challange Time :-
Q. JavaScript program to print table for given number
(8 and 9) using for Loop.
for(var x = 1; x <= 10; x++){
var tableOf = 8;
console.log(tableOf + " x " + x + " = " + (tableOf * x));
}
for(var num = 1; num<=10; num++){
tableOf = 9;
console.log(tableOf + " x " + num + " = " + tableOf*num);
}
