## C++, math, perimeter.cpp

``````/**
* @file
* @brief Implementations for the
* [perimeter](https://en.wikipedia.org/wiki/Perimeter) of various shapes
* @details The  of a shape is the amount of 2D space it takes up.
* All shapes have a formula for their perimeter.
* These implementations support multiple return types.
*
* @author [OGscorpion](https://github.com/OGscorpion)
*/
#define _USE_MATH_DEFINES
#include <cassert>   /// for assert
#include <cmath>     /// for M_PI definition and pow()
#include <cstdint>   /// for uint16_t datatype
#include <iostream>  /// for IO operations

/**
* @namespace math
* @brief Mathematical algorithms
*/
namespace math {
/**
* @brief perimeter of a [square](https://en.wikipedia.org/wiki/Square) (4 * l)
* @param length is the length of the square
* @returns perimeter of square
*/
template <typename T>
T square_perimeter(T length) {
return 4 * length;
}

/**
* @brief perimeter of a [rectangle](https://en.wikipedia.org/wiki/Rectangle) (
* 2(l + w) )
* @param length is the length of the rectangle
* @param width is the width of the rectangle
* @returns perimeter of the rectangle
*/
template <typename T>
T rect_perimeter(T length, T width) {
return 2 * (length + width);
}

/**
* @brief perimeter of a [triangle](https://en.wikipedia.org/wiki/Triangle) (a +
* b + c)
* @param base is the length of the bottom side of the triangle
* @param height is the length of the tallest point in the triangle
* @returns perimeter of the triangle
*/
template <typename T>
T triangle_perimeter(T base, T height, T hypotenuse) {
return base + height + hypotenuse;
}

/**
* @brief perimeter of a
* [circle](https://en.wikipedia.org/wiki/perimeter_of_a_circle) (2 * pi * r)
* @returns perimeter of the circle
*/
template <typename T>
return 2 * M_PI * radius;
}

/**
* @brief perimeter of a
* [parallelogram](https://en.wikipedia.org/wiki/Parallelogram) 2(b + h)
* @param base is the length of the bottom side of the parallelogram
* @param height is the length of the tallest point in the parallelogram
* @returns perimeter of the parallelogram
*/
template <typename T>
T parallelogram_perimeter(T base, T height) {
return 2 * (base + height);
}

/**
* @brief surface perimeter of a [cube](https://en.wikipedia.org/wiki/Cube) ( 12
* * l)
* @param length is the length of the cube
* @returns surface perimeter of the cube
*/
template <typename T>
T cube_surface_perimeter(T length) {
return 12 * length;
}

/**
* @brief surface perimeter of a
* [n-polygon](https://www.cuemath.com/measurement/perimeter-of-polygon/) ( n *
* l)
* @param length is the length of the polygon
* @param sides is the number of sides of the polygon
* @returns surface perimeter of the polygon
*/
template <typename T>
T n_polygon_surface_perimeter(T sides, T length) {
return sides * length;
}

/**
* @brief surface perimeter of a
* [cylinder](https://en.wikipedia.org/wiki/Cylinder) (2 * radius + 2 * height)
* @param height is the height of the cylinder
* @returns surface perimeter of the cylinder
*/
template <typename T>
T cylinder_surface_perimeter(T radius, T height) {
return (2 * radius) + (2 * height);
}
}  // namespace math

/**
* @brief Self-test implementations
* @returns void
*/
static void test() {
// I/O variables for testing
uint16_t int_length = 0;      // 16 bit integer length input
uint16_t int_width = 0;       // 16 bit integer width input
uint16_t int_base = 0;        // 16 bit integer base input
uint16_t int_height = 0;      // 16 bit integer height input
uint16_t int_hypotenuse = 0;  // 16 bit integer hypotenuse input
uint16_t int_sides = 0;       // 16 bit integer sides input
uint16_t int_expected = 0;    // 16 bit integer expected output
uint16_t int_perimeter = 0;   // 16 bit integer output

float float_length = NAN;     // float length input
float float_expected = NAN;   // float expected output
float float_perimeter = NAN;  // float output

double double_length = NAN;     // double length input
double double_width = NAN;      // double width input
double double_height = NAN;     // double height input
double double_expected = NAN;   // double expected output
double double_perimeter = NAN;  // double output

// 1st test
int_length = 5;
int_expected = 20;
int_perimeter = math::square_perimeter(int_length);

std::cout << "perimeter OF A SQUARE (int)" << std::endl;
std::cout << "Input Length: " << int_length << std::endl;
std::cout << "Expected Output: " << int_expected << std::endl;
std::cout << "Output: " << int_perimeter << std::endl;
assert(int_perimeter == int_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 2nd test
float_length = 2.5;
float_expected = 10;
float_perimeter = math::square_perimeter(float_length);

std::cout << "perimeter OF A SQUARE (float)" << std::endl;
std::cout << "Input Length: " << float_length << std::endl;
std::cout << "Expected Output: " << float_expected << std::endl;
std::cout << "Output: " << float_perimeter << std::endl;
assert(float_perimeter == float_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 3rd test
int_length = 4;
int_width = 7;
int_expected = 22;
int_perimeter = math::rect_perimeter(int_length, int_width);

std::cout << "perimeter OF A RECTANGLE (int)" << std::endl;
std::cout << "Input Length: " << int_length << std::endl;
std::cout << "Input Width: " << int_width << std::endl;
std::cout << "Expected Output: " << int_expected << std::endl;
std::cout << "Output: " << int_perimeter << std::endl;
assert(int_perimeter == int_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 4th test
double_length = 2.5;
double_width = 5.7;
double_expected = 16.4;
double_perimeter = math::rect_perimeter(double_length, double_width);

std::cout << "perimeter OF A RECTANGLE (double)" << std::endl;
std::cout << "Input Length: " << double_length << std::endl;
std::cout << "Input Width: " << double_width << std::endl;
std::cout << "Expected Output: " << double_expected << std::endl;
std::cout << "Output: " << double_perimeter << std::endl;
assert(double_perimeter == double_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 5th test
int_base = 10;
int_height = 3;
int_hypotenuse = 5;
int_expected = 18;
int_perimeter =
math::triangle_perimeter(int_base, int_height, int_hypotenuse);

std::cout << "perimeter OF A TRIANGLE" << std::endl;
std::cout << "Input Base: " << int_base << std::endl;
std::cout << "Input Height: " << int_height << std::endl;
std::cout << "Expected Output: " << int_expected << std::endl;
std::cout << "Output: " << int_perimeter << std::endl;
assert(int_perimeter == int_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 6th test
double_expected =
37.69911184307752;  // rounded down because the double datatype
// truncates after 14 decimal places

std::cout << "perimeter OF A CIRCLE" << std::endl;
std::cout << "Expected Output: " << double_expected << std::endl;
std::cout << "Output: " << double_perimeter << std::endl;
assert(double_perimeter == double_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 7th test
int_base = 6;
int_height = 7;
int_expected = 26;
int_perimeter = math::parallelogram_perimeter(int_base, int_height);

std::cout << "perimeter OF A PARALLELOGRAM" << std::endl;
std::cout << "Input Base: " << int_base << std::endl;
std::cout << "Input Height: " << int_height << std::endl;
std::cout << "Expected Output: " << int_expected << std::endl;
std::cout << "Output: " << int_perimeter << std::endl;
assert(int_perimeter == int_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 8th test
double_length = 5.5;
double_expected = 66.0;
double_perimeter = math::cube_surface_perimeter(double_length);

std::cout << "SURFACE perimeter OF A CUBE" << std::endl;
std::cout << "Input Length: " << double_length << std::endl;
std::cout << "Expected Output: " << double_expected << std::endl;
std::cout << "Output: " << double_perimeter << std::endl;
assert(double_perimeter == double_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 9th test
int_sides = 7;
int_length = 10;
int_expected = 70;
int_perimeter = math::n_polygon_surface_perimeter(int_sides, int_length);

std::cout << "SURFACE perimeter OF A N-POLYGON" << std::endl;
std::cout << "Input Sides: " << int_sides << std::endl;
std::cout << "Input Length: " << int_length << std::endl;
std::cout << "Expected Output: " << int_expected << std::endl;
std::cout << "Output: " << int_perimeter << std::endl;
assert(int_perimeter == int_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;

// 10th test
double_height = 7.0;
double_expected = 22.0;
double_perimeter =

std::cout << "SURFACE perimeter OF A CYLINDER" << std::endl;
std::cout << "Input Height: " << double_height << std::endl;
std::cout << "Expected Output: " << double_expected << std::endl;
std::cout << "Output: " << double_perimeter << std::endl;
assert(double_perimeter == double_expected);
std::cout << "TEST PASSED" << std::endl << std::endl;
}

/**
* @brief Main function
* @returns 0 on exit
*/
int main() {
test();  // run self-test implementations
return 0;
}
``````