Lifetime and scope comparison - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable with block scope.

C

void function() {
    [1] int x = 5;
}

Drag options to blanks, or click blank then click option'

Aauto

Bstatic

Cextern

Dregister

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'static' inside a function makes the variable retain its value between calls, changing its lifetime.

The auto keyword declares a variable with block scope and automatic storage duration by default in C.

2fill in blank

medium

Complete the code to declare a variable with static lifetime inside a function.

C

void function() {
    [1] int count = 0;
    count++;
    printf("%d", count);
}

Drag options to blanks, or click blank then click option'

Aauto

Bstatic

Cregister

Dextern

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'auto' inside a function resets the variable each call.

The static keyword inside a function gives the variable static lifetime, so it keeps its value between function calls.

3fill in blank

hard

Fix the error in the code to correctly declare an external variable.

C

[1] int count;

void function() {
    count = 5;
}

Drag options to blanks, or click blank then click option'

Astatic

Bauto

Cextern

Dregister

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'static' limits the variable to the current file scope.

The extern keyword declares a variable defined elsewhere, allowing access across files or scopes.

4fill in blank

hard

Fill both blanks to declare a global variable with internal linkage and initialize it.

C

[1] int [2] = 10;

Drag options to blanks, or click blank then click option'

Astatic

Bextern

Ccount

Dauto

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'extern' at global scope declares but does not define the variable.

static at global scope gives internal linkage, and count is the variable name.

5fill in blank

hard

Fill all three blanks to create a function that uses a static local variable and prints it.

C

void [1]() {
    [2] int [3] = 0;
    [3]++;
    printf("%d", [3]);
}

Drag options to blanks, or click blank then click option'

Aincrement

Bstatic

Ccounter

Dauto

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'auto' resets the variable each call.

The function name is increment, the variable is declared static to keep its value, and the variable name is counter.