Learn What are Functions? | Introduction to Functions

Functions are fundamental building blocks in programming. They are reusable blocks of code designed to perform a specific task. Functions help make code more organized, readable, and easier to maintain. By using functions, you can break a large, complex program into smaller, manageable subroutines.

main.cpp


              1234
            
int main() // `main` is the name of a function
{
	return 0;
}

Note

The name main is already reserved by the C++ language. Therefore, when declaring a function with this name, the compiler will generate an error.

Creating a function involves several key steps to ensure it performs a specific task and integrates seamlessly into your program. A function consists of a return type, a name, parameters (if needed), and a body where the logic resides.

get_bank_name.h


              123456
            
// Returns the name of the bank
std::string get_bank_name() // Function declaration with return type and name
{ 
    std::string bank_name = "Future Savings Bank"; // Store bank name
    return bank_name; // Return it to the caller
}

After creating a function, the next step is to call it. Calling a function executes the code inside it and allows you to use its result (if it returns a value).

main.cpp


              1234567891011121314
            
#include <iostream>
#include <string>

// Function to return the name of the bank
std::string get_bank_name()
{ 
    std::string bank_name = "Future Savings Bank";
    return bank_name; // Return the name of the bank
}

int main()
{
	std::cout << "Name of the bank: " << get_bank_name() << std::endl;
}

Converting currencies is a common real-life task, especially in global transactions or travel. By creating a function, we can simplify this process, making the conversion reusable and efficient.

main.cpp


              123456789101112131415
            
#include <iostream>

// Function to convert USD to Euros
double convert_usd_to_eur(double usd_amount)
{
    const double exchange_rate = 0.91;
    double euros = usd_amount * exchange_rate;
    return euros;
}

int main()
{
    double usd = 100.0; // Amount in USD
    std::cout << usd << " USD = " << convert_usd_to_eur(usd) << " EUR" << std::endl;
}

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Section 5. Chapter 1

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main.cpp


              1234
            
int main() // `main` is the name of a function
{
	return 0;
}

Note

The name main is already reserved by the C++ language. Therefore, when declaring a function with this name, the compiler will generate an error.

get_bank_name.h


              123456
            
// Returns the name of the bank
std::string get_bank_name() // Function declaration with return type and name
{ 
    std::string bank_name = "Future Savings Bank"; // Store bank name
    return bank_name; // Return it to the caller
}

After creating a function, the next step is to call it. Calling a function executes the code inside it and allows you to use its result (if it returns a value).

main.cpp


              1234567891011121314
            
#include <iostream>
#include <string>

// Function to return the name of the bank
std::string get_bank_name()
{ 
    std::string bank_name = "Future Savings Bank";
    return bank_name; // Return the name of the bank
}

int main()
{
	std::cout << "Name of the bank: " << get_bank_name() << std::endl;
}

Converting currencies is a common real-life task, especially in global transactions or travel. By creating a function, we can simplify this process, making the conversion reusable and efficient.

main.cpp


              123456789101112131415
            
#include <iostream>

// Function to convert USD to Euros
double convert_usd_to_eur(double usd_amount)
{
    const double exchange_rate = 0.91;
    double euros = usd_amount * exchange_rate;
    return euros;
}

int main()
{
    double usd = 100.0; // Amount in USD
    std::cout << usd << " USD = " << convert_usd_to_eur(usd) << " EUR" << std::endl;
}

Everything was clear?

Thanks for your feedback!

Section 5. Chapter 1