How to Safely Assign an Integer Value to an Integer Pointer in Go?

Setting an Int Pointer to an Int Value in Go

When trying to assign a value to a pointer variable, it's crucial to ensure the pointer is not nil. Attempting to dereference a nil pointer can lead to a runtime panic, as you experienced.

Solution:

To set the pointed value, the pointer must point to something valid. You can obtain a pointer to a zero-valued int using the new() function:

guess := new(int)
*guess = 12345

This allocates memory for the int variable and sets the pointer to point to that memory. Now you can modify the pointed value through the pointer.

Simplified Declaration:

You can simplify the declaration and initialization using a short variable declaration:

guess := new(int)
*guess = 12345

Alternative Approach:

You can also assign the address of an existing variable to the pointer:

value := 12345
guess := &value

This modifies the pointer value, not the pointed value. However, in this simple example, the effect is similar.

Modification of Pointed Value:

Changing the pointed value through the pointer will also change the value of the variable it points to. Conversely, modifying the value of the variable will affect the pointed value:

var value int
guess := &value
value = 12345
fmt.Println(*guess)
// Prints: 12345

Using a pointer provides a convenient way to indirectly modify the value of a variable. However, it's important to initialize the pointer properly to avoid nil pointer errors and ensure data integrity.

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