Types of control statements in javascript w3schools

Heidi 161 Published: 09/23/2024

Types of control statements in javascript w3schools

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W3Schools provides a comprehensive guide on types of control statements in JavaScript, which are essential for controlling the flow of your program. Let's dive into the details:

If Statement: The if statement is used to execute a block of code if a specified condition is true.

Syntax: if (condition) { code }

Example: if (x > 5) { console.log("x is greater than 5"); }

Else Statement: The else statement is used in combination with the if statement, and it executes a block of code if the specified condition is false.

Syntax: if (condition) { code } else { other_code }

Example: if (x > 5) { console.log("x is greater than 5"); } else { console.log("x is less than or equal to 5"); }

Switch Statement: The switch statement is used when you need to execute a specific block of code based on the value of an expression.

Syntax: switch (expression) { case value1: code; break; case value2: code; break; ... default: code; }

Example: let day = "Sunday"; switch (day) { case "Saturday": console.log("Today is Saturday"); break; case "Sunday": console.log("Today is Sunday"); break; default: console.log("Unknown day of the week"); }

Do-While Statement: The do-while statement is similar to a while loop, but it executes the code block at least once before checking the condition.

Syntax: do { code } while (condition);

Example: let i = 0; do { console.log(i); i++; } while (i < 3);

While Statement: The while statement is used to execute a block of code as long as a specified condition is true.

Syntax: while (condition) { code }

Example: let i = 0; while (i < 3) { console.log(i); i++; }

For Loop: The for loop is used when you need to execute a block of code repeatedly with an initialization, condition, and increment.

Syntax: for (initialization; condition; increment) { code }

Example: for (let i = 0; i < 3; i++) { console.log(i); }

For-Each Loop: The for-each loop is used to execute a block of code repeatedly with an iterable object, like an array or string.

Syntax: for (value of iterable) { code }

Example: let colors = ["red", "green", "blue"]; for (const color of colors) { console.log(color); }

Try-Catch Statement: The try-catch statement is used to catch and handle exceptions (errors) that may occur during the execution of your program.

Syntax: try { code } catch (error) { code }

Example: try { throw new Error("Error occurred"); } catch (error) { console.log(error); }

Finally Statement: The finally statement is used to execute a block of code regardless of whether an exception was thrown or not.

Syntax: try { code } catch (error) { code } finally { code }

Example: try { throw new Error("Error occurred"); } catch (error) { console.log(error); } finally { console.log("Finally executed"); }

In summary, these control statements in JavaScript enable you to control the flow of your program and execute specific blocks of code based on conditions, exceptions, or iterative processes. By mastering these statements, you can create more robust, efficient, and maintainable programs!

What are the conditional statements in JavaScript?

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In JavaScript, a conditional statement is used to execute different code paths based on certain conditions or criteria. These statements are also known as control flow statements or branching statements. The goal of using conditional statements is to make the program more dynamic and flexible by allowing it to make decisions and react to different situations.

Here are some common types of conditional statements in JavaScript:

If Statement: This is the most basic type of conditional statement. It consists of an if clause, a condition, and a block of code that will be executed if the condition is true. The syntax for an if statement is:

if (condition) {
// code to execute if condition is true
}

For example:

let x = 5;
if (x > 10) {
console.log("x is greater than 10");
} else {
console.log("x is less than or equal to 10");
}

If-Else Statement: This statement is an extension of the if statement and allows you to execute different code paths based on whether the condition is true or false. The syntax for an if-else statement is:

if (condition) {
// code to execute if condition is true
} else {
// code to execute if condition is false
}

For example:

let x = 5;
if (x > 10) {
console.log("x is greater than 10");
} else {
console.log("x is less than or equal to 10");
}

If-Else-If Statement: This statement allows you to execute different code paths based on whether the condition is true, false, or something in between. The syntax for an if-else-if statement is:

if (condition1) {
// code to execute if condition1 is true
} else if (condition2) {
// code to execute if condition1 is false and condition2 is true
} else {
// code to execute if both conditions are false
}

For example:

let x = 5;
if (x > 10) {
console.log("x is greater than 10");
} else if (x === 5) {
console.log("x is equal to 5");
} else {
console.log("x is less than 5");
}

Switch Statement: This statement allows you to execute different code paths based on the value of an expression or variable. The syntax for a switch statement is:

switch (expression) {
case value1:
// code to execute if expression is equal to value1
break;
case value2:
// code to execute if expression is equal to value2
break;
default:
// code to execute if none of the above cases match
}

For example:

let day = "Saturday";
switch (day) {
case "Monday":
case "Tuesday":
case "Wednesday":
console.log("Weekdays");
break;
case "Friday":
console.log("Almost weekend!");
break;
default:
console.log("Weekend!");
}

Conditional Operator: This is a shorthand way to write if-else statements using the ternary operator (?:). The syntax for the conditional operator is:

expression ? true_value : false_value

For example:

let x = 5;
console.log(x > 10 ? "x is greater than 10" : "x is less than or equal to 10");

In conclusion, conditional statements in JavaScript are used to make decisions and execute different code paths based on certain conditions. These statements include if statements, if-else statements, if-else-if statements, switch statements, and the conditional operator. Each type of statement has its own syntax and use cases, but they all serve the same purpose: making your program more dynamic and flexible.