Using cout for output in C++ - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of chained cout statements

What is the output of this C++ code?

C++

#include <iostream>
int main() {
    std::cout << "Hello" << ", " << "World!" << std::endl;
    return 0;
}

A Hello, World!\n

B Hello World!\n

C Hello,World!\n

D Hello\n, \nWorld!\n

💡 Hint

Look at how the strings and commas are chained with << operators.

The code prints the strings exactly as chained with <<, so it outputs 'Hello, World!' followed by a newline.

❓ Predict Output

intermediate

Output with multiple cout lines

What will be printed when this code runs?

C++

#include <iostream>
int main() {
    std::cout << "Line 1" << std::endl;
    std::cout << "Line 2";
    std::cout << " Line 3" << std::endl;
    return 0;
}

A Line 1\nLine 2 Line 3\n

B Line 1\nLine 2 Line 3

C Line 1\nLine 2\nLine 3\n

D Line 1 Line 2 Line 3\n

💡 Hint

Check where std::endl is used to add new lines.

The first cout ends with std::endl adding a newline. The second cout prints without newline, so the third cout continues on the same line and ends with std::endl.

❓ Predict Output

advanced

Output with mixed data types using cout

What is the output of this code snippet?

C++

#include <iostream>
int main() {
    int a = 5;
    double b = 3.2;
    std::cout << "a = " << a << ", b = " << b << std::endl;
    return 0;
}

A a = 5 b = 3.2\n

B a = 5, b = 3.2\n

C a = 5, b = 3.200000\n

D a = 5, b = 3.20\n

💡 Hint

By default, double prints with minimal decimals unless formatted.

The double value prints as 3.2 by default without extra trailing zeros.

❓ Predict Output

advanced

Output with cout and escape sequences

What will this program print?

C++

#include <iostream>
int main() {
    std::cout << "First Line\nSecond Line\tTabbed" << std::endl;
    return 0;
}

A

First Line\nSecond Line Tabbed

B First Line\nSecond Line\tTabbed\n

C

First Line Second Line Tabbed

D

First Line
Second Line	Tabbed

💡 Hint

Escape sequences like \n and \t create new lines and tabs in output.

The \n creates a new line and \t adds a tab space in the output.

❓ Predict Output

expert

Output of cout with pointer and address

What is the output of this code?

C++

#include <iostream>
int main() {
    int x = 10;
    int* p = &x;
    std::cout << "Value: " << *p << ", Address: " << p << std::endl;
    return 0;
}

A Value: 10, Address: *p\n

B Value: 10 Address: 0x7ffee3bff6ac\n

C Value: 10, Address: 0x7ffee3bff6ac\n

D Value: 10, Address: 10\n

💡 Hint

The pointer prints the memory address, which looks like a hex number starting with 0x.

The *p dereferences the pointer to print the value 10, and p prints the memory address in hexadecimal format.