Lære Performing Arithmetic On Variables

We can perform arithmetic on variables storing numbers similar to how we perform operations on raw numerical values.

For example:


              1234
            
let varA = 10;
let varB = 20;

console.log(varA + varB);

The expression varA + varB considers varA and varB as if they were raw numbers.

The right-hand side of the assignment statement is always evaluated before feeding the result into the variable on the left side. Because of this, we can make changes to the value of a variable:


              1234
            
let exampleVar = 100;
console.log(exampleVar); // Before
exampleVar = exampleVar + 100;
console.log(exampleVar); // After

This above code adds 100 to the value of exampleVar.

However, the same operation can also be performed using a shorter syntax:


              123
            
let exampleVar = 100;
exampleVar += 100;
console.log(exampleVar);

This syntax works for any supported arithmetic operation.

For example:


              1234
            
exampleVar *= 100; // Multiplication
exampleVar /= 100; // Division
exampleVar **= 100; // Raising to a Power
exampleVar %= 100; // Remainder

A short syntax for incrementing the value of a variable by 1 is by using the ++ operator. For example:


              1234
            
let varA = 9;
console.log(varA); // Before
varA++;
console.log(varA); // After

We can use -- for decrementing a variable by 1:


              1234
            
let varA = 5;
console.log(varA); // Before
varA--;
console.log(varA); // After

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Sektion 1. Kapitel 22

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We can perform arithmetic on variables storing numbers similar to how we perform operations on raw numerical values.

For example:


              1234
            
let varA = 10;
let varB = 20;

console.log(varA + varB);

The expression varA + varB considers varA and varB as if they were raw numbers.

The right-hand side of the assignment statement is always evaluated before feeding the result into the variable on the left side. Because of this, we can make changes to the value of a variable:


              1234
            
let exampleVar = 100;
console.log(exampleVar); // Before
exampleVar = exampleVar + 100;
console.log(exampleVar); // After

This above code adds 100 to the value of exampleVar.

However, the same operation can also be performed using a shorter syntax:


              123
            
let exampleVar = 100;
exampleVar += 100;
console.log(exampleVar);

This syntax works for any supported arithmetic operation.

For example:


              1234
            
exampleVar *= 100; // Multiplication
exampleVar /= 100; // Division
exampleVar **= 100; // Raising to a Power
exampleVar %= 100; // Remainder

A short syntax for incrementing the value of a variable by 1 is by using the ++ operator. For example:


              1234
            
let varA = 9;
console.log(varA); // Before
varA++;
console.log(varA); // After

We can use -- for decrementing a variable by 1:


              1234
            
let varA = 5;
console.log(varA); // Before
varA--;
console.log(varA); // After

Var alt klart?

Tak for dine kommentarer!

Sektion 1. Kapitel 22

Performing Arithmetic On Variables

1. What will the following code output?

2. What is the purpose of the following line of code?

3. Which of the following is the correct shorthand for the operation `exampleVar = exampleVar - 50`?

4. What will the following code output?

Performing Arithmetic On Variables

1. What will the following code output?

2. What is the purpose of the following line of code?

3. Which of the following is the correct shorthand for the operation `exampleVar = exampleVar - 50`?

4. What will the following code output?

Performing Arithmetic On Variables

1. What will the following code output?

2. What is the purpose of the following line of code?

3. Which of the following is the correct shorthand for the operation exampleVar = exampleVar - 50?

4. What will the following code output?

Performing Arithmetic On Variables

1. What will the following code output?

2. What is the purpose of the following line of code?

3. Which of the following is the correct shorthand for the operation exampleVar = exampleVar - 50?

4. What will the following code output?

3. Which of the following is the correct shorthand for the operation `exampleVar = exampleVar - 50`?

3. Which of the following is the correct shorthand for the operation `exampleVar = exampleVar - 50`?