02.variables in c++

Variables in c++

Variable are used in C++, where we need storage for any value, which will change in program. Variable can be declared in multiple ways...

1-displaying a variable

#include<iostream>
using namespace std;
 int main ()

 {
 int x = 23;

    cout<<"hello world"<<endl;
    cout<<"my name is John"<<endl;
    cout <<"i am \n";
    cout<<x;
    cout<<"year old";

    return 0;
    }

Output:-

Note:-The integer can be declared in either way and you will get the same result..

int x = 23;
or
int x;
x=23;

also in the code, The variables shall never be written in quotation marks,, because if you will type

 cout<<"x" ;

then it will type the letter x, and not the variable x

---

EXAMPLE 2- Adding two variables

#include<iostream>
 using namespace std;
 int main ()

 {
 int a=50;
int b=25;

 int result = a+b;

      cout<<result;

     return 0;
 }








In above example we predefined the value of the variable..but if we want user to select a value for that variable, we use cin with an extraction operator(<<)

Note that cout is written with insersion operator (>>)

---

Example 3- Doubling a number given by user



#include<iostream>
 using namespace std;
 int main () 

 {
 int a; 
 cout<<"please enter a numbers to be doubled "<<endl;

        cin>>a;
        cout<<(a*2); 

        return 0; 
 }


Output:-

---

Example 4- Accepting multiple inputs from user

#include<iostream>
using namespace std;
int main ()


{

int a,b,c;

cout<<"please enter a number"<<endl;
cin>>a ;
cout<<"please enter another number"<<endl;
cin>>b ;

c=a+b;

cout<<"the sum of two numbers is"<<c ;


return 0;

}

---

Example 5- Declaring an integer as decimal

if you want to declare an variable as decimal , float is used e.g float a,b,c

#include<iostream>
using namespace std;
int main ()


{

float a,b,c;

cout<<"please enter a number"<<endl;
cin>>a ;
cout<<"please enter another number"<<endl;
cin>>b ;

c=a+b;

cout<<"the sum of two numbers is"<<c ;


return 0;


}

In the next post, you will learn about conditional statements..
Conditional statements