Control Structures: Conditionals and Loops

In JavaScript, there are several types of control structures for conditionals and loops.

Conditionals:

1. If statement: The if statement in JavaScript is similar to other programming languages. It evaluates a condition and executes a block of code if the condition is true. Example:

if (x > 0) {
  console.log("x is positive");
}

2. If-else statement: The if-else statement in JavaScript is also similar to other programming languages. It evaluates a condition and executes a block of code if the condition is true, otherwise it executes another block of code. Example:

if (x > 0) {
  console.log("x is positive");
} else {
  console.log("x is not positive");
}

3. Switch statement: The switch statement in JavaScript is used to select one of many code blocks to be executed. It evaluates an expression and compares it to multiple cases. If a case matches the expression, the corresponding block of code is executed. Example:

switch (color) {
  case "red":
    console.log("The color is red");
    break;
  case "blue":
    console.log("The color is blue");
    break;
  default:
    console.log("The color is not red or blue");
    break;
}

Loops:

1. While loop: The while loop in JavaScript executes a block of code as long as a specified condition is true. Example:

while (i < 5) {
  console.log(i);
  i++;
}

2. Do-while loop: The do-while loop in JavaScript is similar to the while loop, but it executes the block of code first, and then checks if the condition is true. Example:

do {
  console.log(i);
  i++;
} while (i < 5);

3. For loop: The for loop in JavaScript is used to loop through a block of code a specified number of times. Example:

for (var i = 0; i < 5; i++) {
  console.log(i);
}