Built-in data types in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an integer variable named age.

C++

int [1] = 25;

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

Aage

Bvalue

Cnumber

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using a keyword as a variable name.

Forgetting to declare the variable type.

The keyword int declares an integer variable. Here, age is the variable name.

2fill in blank

medium

Complete the code to declare a floating-point variable named price with value 19.99.

C++

float [1] = 19.99f;

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

Avalue

Bcost

Camount

Dprice

Attempts:

3 left

💡 Hint

Common Mistakes

Using an integer type for decimal numbers.

Missing the f suffix for float literals.

The float type stores decimal numbers. The variable name price matches the context.

3fill in blank

hard

Fix the error in the code by choosing the correct data type for the variable isOpen.

C++

[1] isOpen = true;

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

Ainteger

Bstring

Cbool

Dfloat

Attempts:

3 left

💡 Hint

Common Mistakes

Using string or float for boolean values.

Using integer which is not a valid C++ type.

The bool type stores true or false values. Here, isOpen should be declared as bool.

4fill in blank

hard

Fill both blanks to declare a character variable named grade with value 'A'.

C++

char [1] = [2];

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

Agrade

B'A'

C"A"

Dletter

Attempts:

3 left

💡 Hint

Common Mistakes

Using double quotes for characters (which makes it a string).

Using an incorrect variable name.

The char type stores a single character. The variable name is grade and the value must be a character literal 'A'.

5fill in blank

hard

Fill both blanks to declare a double variable named distance with value 123.456.

C++

double [1] = [2];

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

Adistance

B123.456

C123.456f

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using float suffix f with double type.

Using an unrelated variable name.

The double type stores decimal numbers with double precision. The variable name is distance and the value is 123.456 (without f suffix).

Practice

1.

Which built-in data type in C++ is used to store whole numbers without decimals?

easy

A. int

B. double

C. char

D. bool

Solution

1. Step 1: Understand data types for numbers

   Whole numbers without decimals are stored in integer types.

2. Step 2: Identify the integer type in C++

   The int type stores whole numbers like 1, 2, -5.

3. Final Answer:

   int -> Option A

4. Quick Check:

   Whole numbers = int [OK]

Hint: Whole numbers use int type in C++ [OK]

Common Mistakes:

• Choosing double for whole numbers
• Using char for numbers
• Confusing bool with numbers

2.

Which of the following is the correct way to declare a variable of type char in C++?

?

easy

A. char letter = 65

B. char letter = "A";

C. char letter = A;

D. char letter = 'A';

Solution

1. Step 1: Understand char initialization

   Characters must be enclosed in single quotes in C++.

2. Step 2: Check each option

   char letter = 'A'; uses single quotes correctly. char letter = "A"; uses double quotes (string). char letter = A; misses quotes. char letter = 65; uses an int, which is allowed but not typical for char.

3. Final Answer:

   char letter = 'A'; -> Option D

4. Quick Check:

   char uses single quotes for characters [OK]

Hint: Use single quotes for char values [OK]

Common Mistakes:

• Using double quotes for char
• Missing quotes around character
• Assigning int without cast

3.

What will be the output of the following C++ code?

#include <iostream>
int main() {
    bool flag = 0;
    if (flag) {
        std::cout << "True";
    } else {
        std::cout << "False";
    }
    return 0;
}

medium

A. True

B. False

C. 0

D. 1

Solution

1. Step 1: Understand bool initialization

   The variable flag is set to 0, which means false in boolean context.

2. Step 2: Check the if condition

   Since flag is false, the else block runs, printing "False".

3. Final Answer:

   False -> Option B

4. Quick Check:

   bool 0 means false [OK]

Hint: bool 0 means false, else block runs [OK]

Common Mistakes:

• Thinking 0 is true
• Expecting numeric output
• Confusing bool with int

4.

Identify the error in this C++ code snippet:

double price = 9.99;
char letter = "B";
bool isAvailable = true;

medium

A. Incorrect bool value assignment

B. Missing semicolon after double declaration

C. Using double quotes for char variable

D. No errors in the code

Solution

1. Step 1: Check char variable initialization

   The variable letter is declared as char but assigned with double quotes, which is incorrect.

2. Step 2: Verify other lines

   The double and bool declarations are correct with semicolons and proper values.

3. Final Answer:

   Using double quotes for char variable -> Option C

4. Quick Check:

   char needs single quotes, not double [OK]

Hint: char must use single quotes, not double quotes [OK]

Common Mistakes:

• Using double quotes for char
• Missing semicolons
• Wrong bool literals

5.

You want to store a person's age, initial letter of their name, and whether they are a student. Which built-in data types should you use in C++?

medium

A. int for age, char for initial, bool for student status

B. double for age, string for initial, int for student status

C. char for age, int for initial, bool for student status

D. bool for age, char for initial, double for student status

Solution

1. Step 1: Choose type for age

   Age is a whole number, so int is suitable.

2. Step 2: Choose type for initial letter

   Initial is a single character, so char fits.

3. Step 3: Choose type for student status

   Student status is yes/no, so bool is best.

4. Final Answer:

   int for age, char for initial, bool for student status -> Option A

5. Quick Check:

   Whole number = int, letter = char, yes/no = bool [OK]

Hint: Use int for numbers, char for letters, bool for yes/no [OK]

Common Mistakes:

• Using double for age
• Using string for single char
• Using int for boolean values