Conditional Statements in JavaScript.

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• Conditional statements are used to make decisions in a program.

• They check whether a condition is true or false.

• JavaScript provides if, else, and else if for conditional statements.

• These statements help decide which block of code should run.

• They are commonly used when a program needs to make a decision.

If Statement

• The if statement is used to check a condition.
• If the condition is true, the code inside the if block will run.
• If the condition is false, the code inside the block will not run.

Example:
let age = 20;

if (age >= 18) {
console.log("You are eligible to vote");
}

Output:

You are eligible to vote

Else Statement

• The else statement is used when the if condition is false.
• It provides an alternative block of code to run.
• If the if condition is true, the else block will not run.
• It is used to handle the opposite condition.
• else is always used with an if statement.

Example:

let age = 16;

if (age >= 18) {
console.log("You are eligible to vote");
} else {
console.log("You are not eligible to vote");
}

Output:
You are not eligible to vote

Else If Statement

• The else if statement is used to check another condition.
• It is used when the first if condition is false.
• We can use multiple else if conditions in a program.
• The first true condition will be executed.
• It is useful for checking multiple conditions.

Example:
let mark = 75;

if (mark >= 90) {
console.log("A Grade");
} else if (mark >= 60) {
console.log("B Grade");
} else {
console.log("C Grade");
}

Output:

B Grade

nested

Nested If Statement

• A nested if means using an if statement inside another if statement.

• The inner if condition is checked only when the outer if condition is true.

• It is used to check conditions step by step.

• A nested if can have another if inside it.

• This helps handle multiple levels of conditions.

Example:

let age = 20;
let hasId = true;

if (age >= 18) {
if (hasId) {
console.log("Entry allowed");
}
}

Output:

Entry allowed
swited

Switch Statement

• The switch statement is used to check a value against multiple cases.

• It runs the code for the matching case.

• The break statement stops the switch after a match.

  • The default case runs when no case matches.

• It is useful when we have multiple possible values.

Example:
let day = 2;

switch (day) {
case 1:
console.log("Monday");
break;

case 2:
    console.log("Tuesday");
    break;

default:
    console.log("Invalid day");

}

Output:

Tuesday

Ternary Operator (? :)

• The ternary operator is a short form of if...else.

*It checks a condition and returns one of two values.

• ? is used for the true condition.

• : is used for the false condition.

• It is useful for writing simple conditions in one line.

Example:

let age = 20;

let result = age >= 18 ? "Eligible" : "Not Eligible";

console.log(result);

Output:

Eligible