Built-in data types in C++ - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of integer and floating-point operations

What is the output of the following C++ code?

C++

#include <iostream>
int main() {
    int a = 5;
    double b = 2.0;
    std::cout << a / b << std::endl;
    return 0;
}

A 2

B 2.50

C 2.5

D 2.0

💡 Hint

Remember that dividing an int by a double results in a double.

The integer 5 is promoted to double 5.0, then divided by 2.0, resulting in 2.5.

❓ Predict Output

intermediate

Size of built-in data types

What is the output of this C++ code on a typical 64-bit system?

C++

#include <iostream>
int main() {
    std::cout << sizeof(char) << "," << sizeof(int) << "," << sizeof(long long) << std::endl;
    return 0;
}

A 1,4,8

B 1,8,8

C 1,4,4

D 2,4,8

💡 Hint

On most 64-bit systems, char is 1 byte, int is 4 bytes, and long long is 8 bytes.

The sizes reflect typical memory allocation: char=1 byte, int=4 bytes, long long=8 bytes.

🧠 Conceptual

advanced

Understanding signed and unsigned integer behavior

What will be the output of this C++ code snippet?

C++

#include <iostream>
int main() {
    unsigned int x = 0;
    std::cout << x - 1 << std::endl;
    return 0;
}

A 4294967295

B 0

C -1

D Compilation error

💡 Hint

Unsigned integers wrap around when subtracting beyond zero.

Subtracting 1 from 0 in unsigned int wraps to the maximum value (2^32 - 1 = 4294967295).

❓ Predict Output

advanced

Boolean type and implicit conversion

What is the output of this C++ code?

C++

#include <iostream>
int main() {
    bool flag = 5;
    std::cout << flag << std::endl;
    return 0;
}

A 5

B 1

C true

D 0

💡 Hint

Any non-zero integer assigned to a bool becomes true (1).

In C++, bool stores either 0 (false) or 1 (true). Assigning 5 converts to true (1).

🔧 Debug

expert

Identify the error in this code using built-in types

What error does this C++ code produce when compiled?

C++

#include <iostream>
int main() {
    int x = 10;
    double y = 3.5;
    int z = x / y;
    std::cout << z << std::endl;
    return 0;
}

A No error, output is 3

B Compilation error: cannot assign double to int

C Runtime error: division by zero

D No error, output is 2

💡 Hint

Division of int by double results in double, then assigned to int truncates the decimal.

x / y is 10 / 3.5 = 2.857..., assigned to int z truncates to 2, no errors occur.