# C++ Program to calculate the area of a circle

## Finding the Area of  circle in C++ :-

Here we will discuss how to find the area of a circle when its radius is given using c++ programming language.

The area of a circle can be found by using the formula:
Area of circle= 𝝅R*R

## Working:-

• User gives an input
• The input is stored in a float type variable say rad.
• Another float type variable is taken say circleArea.
• Now using the formula we find the area of the circle of radius rad and store it in circleArea.

• Print the value of circleArea.

### Code in C++

Run
```#include<bits/stdc++.h>
using namespace std;

int main(){

cout<<"Area of circle is "<<area;
}```

### Output

`Area of circle is 28.26`

## Algorithm using diameter :-

• User gives an input (diameter of the circle)
• The input is stored in a float type variable say d.
• Another float type variable is taken say circleArea.
• Now using the formula we find the area of the circle of diameter d and store it in circleArea.

circleArea= (3.14* d* d)/4;

• Print the value of circleArea.

### Code in C++

Run
```#include<bits/stdc++.h>
using namespace std;

int main(){
float d = 6, area;

area=(3.14*d*d)/4;
cout<<"Area of circle is "<<area;
}```

### Output

`Area of circle is 28.26`