Control Structures - CodeToLive

Control Structures in TypeScript

Control structures in TypeScript allow you to control the flow of your program. They include conditional statements (if-else) and loops (for, while).

If-Else Statements

The if-else statement is used to execute a block of code based on a condition.


let age: number = 20;
if (age >= 18) {
    console.log("You are an adult.");
} else {
    console.log("You are a minor.");
}

Ternary Operator

The ternary operator is a concise way to write simple if-else statements.


let age: number = 20;
let message = age >= 18 ? "You are an adult." : "You are a minor.";
console.log(message);

Switch Statement

The switch statement is used to execute one of many code blocks based on the value of an expression.


let day: number = 3;
switch (day) {
    case 1:
        console.log("Monday");
        break;
    case 2:
        console.log("Tuesday");
        break;
    default:
        console.log("Invalid day");
}

Loops

Loops are used to execute a block of code repeatedly. TypeScript supports for, while, and do-while loops.


// For Loop
for (let i = 0; i < 5; i++) {
    console.log(i);
}

// While Loop
let count: number = 0;
while (count < 5) {
    console.log(count);
    count++;
}

// Do-While Loop
let x: number = 0;
do {
    console.log(x);
    x++;
} while (x < 5);

For-Of Loop

The for-of loop is used to iterate over arrays and strings.


let fruits: string[] = ["apple", "banana", "cherry"];
for (let fruit of fruits) {
    console.log(fruit);
}

For-In Loop

The for-in loop is used to iterate over object properties.


let person = { name: "Alice", age: 25 };
for (let key in person) {
    console.log(`${key}: ${person[key]}`);
}

Break and Continue

Use break to exit a loop and continue to skip to the next iteration.


for (let i = 0; i < 10; i++) {
    if (i === 5) {
        break;  // Exit the loop
    }
    if (i % 2 === 0) {
        continue;  // Skip even numbers
    }
    console.log(i);
}

Interactive Code Examples

Try running these examples in your TypeScript environment to see how they work!


// Interactive Example
let numbers: number[] = [1, 2, 3, 4, 5];
for (let number of numbers) {
    console.log(number);
}

Practice Problems

Test your understanding with these practice problems:

Write a TypeScript program to print the first 10 even numbers.
Write a TypeScript program to find the sum of all elements in an array.
Write a TypeScript program to check if a number is prime.

Next: Functions