Common pointer use cases in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a pointer in Go?

A pointer in Go is a variable that stores the memory address of another variable. It allows you to directly access and modify the value stored at that address.

beginner

Why use pointers to modify function arguments in Go?

Using pointers as function arguments allows the function to modify the original variable's value, not just a copy. This is useful for changing data outside the function's scope.

intermediate

How do pointers help with performance in Go?

Pointers avoid copying large data structures by passing their memory address instead. This reduces memory use and speeds up the program.

intermediate

What is the use of pointers with structs in Go?

Pointers to structs let you modify the struct fields directly and efficiently pass large structs without copying all their data.

beginner

How do you declare and use a pointer in Go?

Declare a pointer with * before the type, e.g., var p *int. Use & to get the address of a variable, e.g., p = &x. Use *p to access or change the value at that address.

What does the * operator do when used with a pointer variable in Go?

A Accesses the value stored at the pointer's address

B Declares a new pointer variable

C Gets the address of a variable

D Creates a copy of the variable

The * operator dereferences the pointer, giving access to the value stored at the memory address.

Why might you pass a pointer to a function instead of a value in Go?

A To allow the function to modify the original variable

B To make a copy of the variable

C To prevent the function from changing the variable

D To increase the size of the variable

Passing a pointer lets the function change the original variable by accessing its memory address.

Which of these is a benefit of using pointers with large structs?

A Automatically initializes all fields to zero

B Avoids copying the entire struct, improving performance

C Makes the struct immutable

D Prevents access to struct fields

Pointers let you pass the address of the struct, avoiding expensive copying of large data.

How do you get the memory address of a variable x in Go?

A *x

B x*

C x&

D &x

The & operator returns the memory address of the variable.

What happens if you try to dereference a nil pointer in Go?

A It creates a new variable

B It returns zero value

C The program panics (runtime error)

D It compiles but does nothing

Dereferencing a nil pointer causes a runtime panic because there is no valid memory address.

Explain three common use cases for pointers in Go and why they are useful.

Think about how pointers let you change data and save memory.

Describe how to declare, assign, and use a pointer variable in Go with an example.

Use a simple int variable example.