Input from User in C++

#include<iostream.h>
#include<conio.h>
void main()
{
cout<<"Please Enter any Key to Continue"<<endl;
getch(); //waiting for get character 'user enter key'.
cout<<"Please Enter any Key to clear screen"<<endl;
getch(); //waiting for get character 'user enter key'.
clrscr();
cout<<"Please Enter any Key to Exit";
 getch(); //waiting for get character 'user enter key'.
}

#include<iostream.h>
#include<conio.h>
void main()
{
int num;
cout<<"Enter a number: ";
cin>>num; //user enter integer value storing in 'num' and
cout<<"You have just entered the number: "<<num; //printing 'num' value.
getch();
}

#include<iostream.h>
#include<conio.h>
void main()
{
int a,b,c;
cout<<"Please Enter First Integer"<<endl;
cin>>a; //user enter Integer value storing in 'a'.
cout<<"Please Enter 2nd Integer"<<endl;
cin>>b; //user enter Integer value storing in 'b'.
 c = a + b;
cout<<"The Answer is: "<<c; //printing 'c' value.
getch();
}

#include<iostream.h>
#include<conio.h>
void main()
{
    //assigning values to variables.
int integerVar = 100;
float floatingVar = 331.79;
double doubleVar = 8.44e+11;
char charVar = 'W';
      //printing Variables values.
cout<<"integerVar = "<<integerVar<<endl;
cout<<"floatingVar = "<<floatingVar<<endl;
cout<<"doubleVar = "<<doubleVar<<endl;
cout<<"doubleVar = "<<doubleVar<<endl;
cout<<"charVar = "<<charVar;
getch();
}