Constants in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a constant in Go?

A constant is a fixed value that cannot be changed during the program's execution. It is declared using the keyword const.

beginner

How do you declare a constant in Go?

Use the <code>const</code> keyword followed by the name, optional type, and value. Example: <code>const Pi = 3.14</code>

beginner

Can you change the value of a constant after it is declared?

No, constants cannot be changed once declared. Trying to assign a new value will cause a compile-time error.

intermediate

What types of values can constants hold in Go?

Constants can hold boolean, numeric (integer, float, complex), and string values.

beginner

What is the difference between a constant and a variable in Go?

A constant's value is fixed and cannot change, while a variable's value can be changed during program execution.

Which keyword is used to declare a constant in Go?

A const

B var

C let

D static

The const keyword is used to declare constants in Go.

What happens if you try to change the value of a constant after declaration?

A The value changes successfully

B Compile-time error occurs

C The program compiles and runs normally

D Runtime error occurs

Constants cannot be changed after declaration; trying to do so causes a compile-time error.

Which of these can be a constant value in Go?

A A slice

B A struct

C A map

D An integer

Constants can hold numeric values like integers, but not slices, maps, or structs.

How do you declare multiple constants at once in Go?

A Using multiple <code>const</code> statements

B Using <code>var</code> with <code>const</code>

C Using a <code>const</code> block with parentheses

D Using <code>let</code> keyword

You can declare multiple constants inside a const block using parentheses.

Which of the following is a valid constant declaration in Go?

A const greeting = "Hello"

B const number = []int{1,2,3}

C const pi = math.Pi

D const flag = true

A (string literal) and D (boolean literal) are valid constant declarations. Slices (B) and variables like math.Pi (C) cannot be used as constant initializers.

Explain what a constant is in Go and how it differs from a variable.

Think about whether the value can change after declaration.

Describe how to declare multiple constants together in Go and give an example.

Use parentheses after the const keyword.