C++ code

main.cpp

// AREA FINDER
#include <iostream.h>
#include <conio.h>

void main()
{
    clrscr();
    int userOption;
    float area;
    cout << "AREA FINDER\n";
    cout << "1. Square\n2. Circle\n3. Rectangle\n";
    cout << "Enter option : ";
    cin >> userOption;
    switch (userOption)
    {
        case 1:
            float side;
            cout << "Enter length of side : ";
            cin >> side;
            area = side * side;
            cout << "Area is " << area << " units\n";
            break;
        case 2:
            float radius;
            cout << "Enter radius : ";
            cin >> radius;
            area = 3.14 * radius * radius;
            cout << "Area is " << area << " units\n";
            break;
        case 3:
            float length, width;
            cout << "Enter length : ";
            cin >> length;
            cout << "Enter width : ";
            cin >> width;
            area = length * width;
            cout << "Area is " << area << " units\n";
            break;
        default:
            cout << "WRONG INPUT. ERROR. QUITTING!\n";
    }
    cout << "\n\nEnter any key to exit.\n";
    getch();
}

// GREATEST NUMBER IN 3
// include all header files like in the one above - 
void main()
{
	clrscr();
	float a, b, c;
	cout << "Enter value for a : ";
	cin >> a;
	cout << "Enter value for b : ";
	cin >> b;
	cout << "Enter value for c : ";
	cin >> c;
	if (a > b && a > c)
	{
		cout << a << " is the greatest!\n";
	}
	else if (b > a && b > c)
	{
		cout << b << " is the greatest\n";
	}
	else
	{
		cout << c << " is the greates!\n";
	}
	cout << "Press any key to exit.";
	getch();
}

// CONDITIONAL OPERATORS
// INCLUDE ALL HEADER FILES LIKE ONE ABOCE
void main()
{
	clrscr();
	int a, b;
	cout << "Enter value for a : ";
	cin >> a;
	cout << "Enter value for b : ";
	cin >> b;
	// CHECK
	if (a > b || a == b)
	{
		cout << "Either a is greater than b or equal to it.\n";
	}
	else if ( a > 0 && b > 0)
	{
		cout << "Both the values are positive\n";
	}
	else if ( a < 0 && b > 0 || a > 0 && b < 0)
	{
		cout << "One of the values is positive and the other is negative!\n";
	}
	else
	{
		cout << "None of the conditions were met!\n";
	}
	cout << "Press any key to exit.";
	getch();
}