C++ constant variable program and area of circle program

C++ constant variable program and area of circle program

#Beginner

In gcc c++ compiler using namespace std;

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#include<iostream>

using namespace std;

int main()

{

/* constant variable always denote in capital letter */

const double PI = 3.14159;

//step 1 : read radius from user

cout<<"enter the radius of circle :";

double radius;

cin>>radius;

cout<<endl;

// step 2 : compute area

double area = radius * radius * PI ;

//step 3 : show area

cout<<"area of the circle is : "<<area;

}

copy

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Output

enter the radius of circle :13

area of the circle is : 530.929

[Program finished]

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Constant variable always declared in upper alphabet eg. const double PI ;  you can't use π as variable name therefore pi and PI is allowed but you defined constant the use variable name PI to simply understand the PI variable is constant variable. the const variable can't change the value.

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