# C Program to Find Area and Circumference of Circle

## Program

``````
#include<stdio.h>
#include<conio.h>

#define PI 3.141592

int main()
{
clrscr(); // Clears the screen
circum = 2*PI*r;
printf("Area = %f\n",area);
printf("Circumference = %f",circum);
getch(); // Holds the output

return 0;
}
``````

Output of the above program :

```Enter radius of circle: 5 ↲
Area = 78.539800
Circumference = 31.415920

Note: ↲ indicates ENTER is pressed.
```

## Code Explanation:

1. `#include<stdio.h>`: This line includes the standard input-output library.
2. `#include<conio.h>`: This line includes the "conio" library for console manipulation.
3. `#define PI 3.141592`: This line defines a constant named `PI` with a value of approximately 3.141592.
4. `int main()`: The main function where the program's execution starts.
5. `float radius, area, circum;`: Variables are declared to store the radius, area, and circumference.
6. `clrscr();`: Clears the console screen.
7. `printf("Enter radius of circle: ");`: Prompts the user to enter the radius.
8. `scanf("%f", &radius);`: Reads the radius input from the user.
9. `area = PI * radius * radius;`: Calculates the area of the circle using the formula `area = π * radius^2`.
10. `circum = 2 * PI * radius;`: Calculates the circumference using the formula `circumference = 2 * π * radius`.
11. `printf("Area = %f\n", area);`: Prints the calculated area.
12. `printf("Circumference = %f", circum);`: Prints the calculated circumference.
13. `getch();`: Waits for a character input to hold the output on the screen.
14. `return 0;`: Indicates successful execution of the program.

Note: The use of `conio.h` and its functions might not be compatible with all compilers and systems.