JavaScript Control Flow Statements

What are Control Flow Statements?

Control Flow Statements are used to control the order in which code executes in a program.

Using control flow statements, we can decide:

• Which code should run.
• Which code should be skipped.
• How many times a block of code should run.

JavaScript provides different types of control flow statements.

Some common control flow statements are:

1. if
2. if...else
3. else if
4. switch
5. for loop
6. while loop

1. if Statement

The if statement executes a block of code only when the condition is true.

let marks = 80;

if (marks >= 50) {
    console.log("Pass");
}

Explanation

• let marks = 80; → A variable named marks is created with the value 80.
• if (marks >= 50) → Checks whether the marks are greater than or equal to 50.
• Since the condition is true, "Pass" is printed.

2. if...else Statement

The if...else statement executes one block if the condition is true and another block if the condition is false.

let age = 15;

if (age >= 18) {
    console.log("Eligible to Vote");
} else {
    console.log("Not Eligible to Vote");
}

Explanation

• age stores the value 15.
• The condition checks whether age is greater than or equal to 18.
• The condition is false, so the else block executes.
• "Not Eligible to Vote" is printed.

3. else if Statement

The else if statement is used to check multiple conditions.

let score = 70;

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

Explanation

• score stores the value 70.
• The first condition (score >= 90) is false.
• The second condition (score >= 60) is true.
• So, "Grade B" is printed.

4. switch Statement

The switch statement is used when we have multiple choices.

let day = 6;

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

    case 6:
        console.log("Saturday");
        break;

    default:
        console.log("Invalid Day");
}

Explanation

• day stores the value 6.
• The switch checks all cases.
• case 6 matches the value.
• "Saturday" is printed.
• break stops further execution.

5. for Loop

The for loop is used when we know how many times the code should run.

for (let i = 1; i <= 3; i++) {
    console.log("Hello");
}

Explanation

• let i = 1 → Loop starts from 1.
• i <= 3 → Loop runs while i is less than or equal to 3.
• i++ → Increases the value of i by 1.
• "Hello" is printed three times.

6. while Loop

The while loop executes as long as the condition is true.

let i = 1;

while (i <= 3) {
    console.log(i);
    i++;
}

Explanation

• i starts with the value 1.
• The loop checks whether i is less than or equal to 3.
• The value of i is printed.
• i++ increases the value by 1.
• The loop stops when i becomes 4.

Today, I learned about JavaScript Control Flow Statements such as if, if...else, else if, switch, for, and while. These statements help us control the execution of code and make decisions based on different conditions.
Thank you for reading my blog. I will meet you in the next blog with another JavaScript topic. 👋