#include<iostream>
#include<stdio.h>
#include<conio.h>

using namespace std;

void Krug();
void Kvadrat();
void Pryamoug();

void main(int  argc, char* argv[])
{
int i;
for (int i = 0; i<argc; i++) cout << argv[i] << '\n';


	{ cin>>i;
     if (i = 1)
	 { Krug(); }
	 else  if (i = 2)
	 { Kvadrat(); }
	 else if (i = 3)
	 { Pryamoug(); }
	}

getch();
return  ;
}

void Krug()
{
double Skr, r;
cout<<"Vvedite radius: r=";
cin>>r;
Skr = r*r*3.14;
printf("S =%f \n", Skr);
}

void Kvadrat()
{
double Skv, c;
cout<<"Vvedite storonu kvadrata: c=";
cin>>c;
Skv = c*c;
printf("S =%f \n", Skv);
}

void Pryamoug()
{
double Spr, a, b;
cout<<"Vvedite  1 storonu pryamougulnica: a=";
cin>>a;
cout<<"Vvedite  2 storonu pryamougulnica: b=";
cin>>b;
Spr = a*b;
printf("S =%f \n", Spr);
}