# Write a Program that calculates the area of a circle and accepts radius from the user

By | October 4, 2021

### Problem Statement

We need to write a program in C, C++, and Python that accepts the radius of the circle from the user and calculates its area. To Calculate the area of a circle we can use the following formula

area of the circle (A)= πr2

A = area of a circle

π = pi which value is 3.14

r = radius of the circle.

### C Program that calculates the area of a circle and accepts radius from the user

```#include <stdio.h>

int main()
{
float A, r;

printf("Enter the radius of the circle in cm: ");

scanf("%f", &r);

//area of the circle
A= 3.14*r*r;
printf("The area of the circle is: %.2f cmsq", A);
return 0;
}```

Output

```Enter the radius of the circle in cm: 3
The area of the circle is: 28.26 cmsq```

### C++ Program that calculates the area of a circle and accepts radius from the user

```#include<iostream.h>
#include< conio.h>
#include<math.h>
void main()
{
clrscr();
float A,r;
cout<<"Enter the radius of the circle in cm: ";
cin>>r;
A = 3.14*pow(r,2);
cout<<"The area of the circle is: "<<A <<" cmsq";
getch();
}```

Output:

```Enter the radius of the circle in cm: 3
The area of the circle is: 28.26 cmsq```

### Python:

```r = float(input("Enter the radius of the circle in cm: "))
A = 3.14*(r*r)
print("The area of the circle is:",A,"cmsq")```

Output:

```Enter the radius of the circle in cm: 3
The area of the circle is: 28.26 cmsq```

Wrapping Up!

In this programming tutorial, we learned how to implement a Circle Area calculator in C, C++, and Python. The program is very simple and straightforward all it does, ask the radius value from the user and calculate the area of the circle based on the entered radius in cm sq.