Functions » Examples

Calculate area of a circle

double area_of_circle(double radius) {
	return 3.14159 * radius * radius;
}

💡 Idea: Use the M_PI constant from the <cmath> header instead of 3.14159.

Convert Fahrenheit to Celsius

double fahrenheit_to_celsius(double fahrenheit) {
	return (fahrenheit - 32) * 5 / 9;
}

💡 Idea: create a calculator that can convert between Fahrenheit, Celsius, and Kelvin.

Calculate factorial of a number

int factorial(int n) {
	int result = 1;
	for (int i = 1; i <= n; ++i) {
		result *= i;
	}
	return result;
}

💡 Idea: create a calculator for the binomial coefficient.

Calculate the average of an array of numbers

double average(std::vector<int> arr) {
	double sum = 0;
	for (int i = 0; i < arr.size(); ++i) {
		sum += arr[i];
	}
	return sum / arr.size();
}

Calculate the greatest common divisor of two numbers

int gcd(int a, int b) {
	if (b == 0) return a;
	return gcd(b, a % b);
}

Calculate the power of a number

double power(double base, int exponent) {
	double result = 1;
	for (int i = 0; i < exponent; ++i) {
		result *= base;
	}
	return result;
}

Reverse a string

std::string reverse_string(std::string str) {
	int n = str.length();
	for (int i = 0; i < n / 2; ++i) {
		char temp = str[i];
		str[i] = str[n - i - 1];
		str[n - i - 1] = temp;
	}
	return str;
}

Check if a string is a palindrome

bool is_palindrome(std::string str) {
	int n = str.length();
	for (int i = 0; i < n / 2; ++i) {
		if (str[i] != str[n - i - 1]) return false;
	}
	return true;
}