Ad
float AverageDisplacement(float u, float v, float t) { return ((u + v) / 2) * t; }

This calculator can multiply, divide, add and subtract.

#include <iostream>
#include <string>

class Operations
{
public:
	float Addition(float a, float b) {
		return a + b;
	}
	float Subtraction(float a, float b) {
		return a - b;
	}
	float Multiplication(float a, float b) {
		return a * b;
	}
	float Division(float a, float b) {
		return a / b;
	}
};

void CaculatorInterface();

int main()
{
	CaculatorInterface();
	return 0;
}

void CaculatorInterface() {
	Operations OP;
	
	std::string CNT;
	std::string Op;
	char op;
	float A;
	float B;
	float result;
	
	for (;;) {
		system("cls");
		std::cout << "\n\n\n\n\t\tEnter Integar : ";
		std::cin >> A;
		std::cout << "\n\n\t\tEnter Operator : ";
		std::cin >> op;
		std::cout << "\n\n\t\tEnter Second Integar : ";
		std::cin >> B;

		if (op == '+') {
			result = OP.Addition(A, B);
			Op = "sum";
		}
		if (op == '-') {
			result = OP.Subtraction(A, B);
			Op = "Diffrence";
		}
		if (op == '*') {
			result = OP.Multiplication(A, B);
			Op = "Product";
		}
		if (op == '/') {
			result = OP.Division(A, B);
			Op = "Quationt";
		}

		std::cout << "\n\n\n\t\t" << Op << " : " << result;
		std::cout << "\n\n\t\t";
		std::cin >> CNT;

		if (CNT == "Continue" || CNT == "continue") {
			continue;
		}
		else {
			system("cls");
			std::cout << "\n\n\n\n\t\tInviled Input : " << CNT << "\n\t\t";
			system("PAUSE");
			system("cls");
			exit(0);
		}
	}

	return;
}

This function claculates the area of a Triangle;

float AreaOfTriangle(float w, float h) {
    float A = (w * h) / 2;
    return A;
}