#include <iostream>
using namespace std;
int
main ()
{
char op;
int a, b, c, d;
cout << "if you are want to open calcutor then enter 1" << endl
<< "if you are want to find maximum number out of three then enter 2" <<
endl << "if you are want to find odd-even then enter 3" << endl;
cin >> d;
switch (d)
{
case 1:
cout << "entar first number" << endl;
cin >> a;
cout << "entar second number" << endl;
cin >> b;
cout << "enter the operation( +,-,*,/)" << endl;
cin >> op;
if (op = '/')
{
cout << a << "/" << b << "=" << (float) a / b << endl;
}
else if (op = '-')
{
cout << a << "-" << b << "=" << a - b << endl;
}
else if (op = '*')
{
cout << a << "*" << b << "=" << a * b << endl;
}
else if (op = '+')
{
cout << a << "+" << b << "=" << a + b << endl;
}
break;
case 2:
cout << "enter three number one by one" << endl;
cin >> a >> b >> c;
if (a > b)
{
if (a > c)
{
cout << "maximum number is\t" << a << endl;
}
else
{
cout << "maximum number is\t" << c << endl;
}
}
else if (b > a)
{
if (b > c)
{
cout << "maximum number is\t" << b << endl;
}
else
{
cout << "maximum number is\t" << c << endl;
}
}
break;
case 3:
cout << "enter any number" << endl;
cin >> a;
if (a % 2 == 0)
{
cout << a << "\tis an even number" << endl;
}
else
{
cout << a << "\tis an odd number" << endl;
}
break;
default:
cout << "invalid number";
}
}