Write a C program to input radius of circle from user and find diameter, circumference and area of the given circle using function. How to find diameter, circumference and area of a circle using function in C programming.

Input radius: 10

Output diameter: 20 units

Output circumference: 62.83 units

Output area: 314.16 sq. units

Before moving on to this program also check how to find diameter, circumference and area of a circle without using functions.

Happy coding ;)

**Example:**Input radius: 10

Output diameter: 20 units

Output circumference: 62.83 units

Output area: 314.16 sq. units

### Required knowledge

Basic C programming, FunctionBefore moving on to this program also check how to find diameter, circumference and area of a circle without using functions.

### Program to find diameter, circumference and area using functions

/** * C program to find diameter, circumference and area of a circle using functions */ #include <stdio.h> #include <math.h> //Used for constant PI referred as M_PI /* Function declaration */ double diameter(double radius); double circumference(double radius); double area(double radius); int main() { float radius, dia, circ, ar; /* Reads radius of the circle from user */ printf("Enter radius of the circle: "); scanf("%f", &radius); dia = diameter(radius); //Calls diameter function circ = circumference(radius); //Calls circumference function ar = area(radius); //Calls area function printf("Diameter of the circle = %.2f units\n", dia); printf("Circumference of the circle = %.2f units\n", circ); printf("Area of the circle = %.2f sq. units\n", ar); return 0; } /** * Finds the diameter of a circle whose radius is given */ double diameter(double radius) { return (2 * radius); } /** * Finds circumference of the circle whose radius is given */ double circumference(double radius) { return (2 * M_PI * radius); //M_PI = PI = 3.14 ... } /** * Finds area of the circle whose radius is given */ double area(double radius) { return (M_PI * radius * radius); //M_PI = PI = 3.14 ... }

Output

Enter radius of the circle: 10

Diameter of the circle = 20.00 units

Circumference of the circle = 62.83 units

Area of the circle = 314.16 sq. units

Diameter of the circle = 20.00 units

Circumference of the circle = 62.83 units

Area of the circle = 314.16 sq. units

Happy coding ;)

### You may also like

- Function programming exercises index.
- C program to find cube of any number using functions.
- C program to find maximum and minimum between two numbers using functions.
- C program to check even or odd using functions.
- C program to check prime, strong, armstrong and perfect numbers using functions.
- C program to find all prime numbers between given interval using functions.
- C program to find all perfect numbers between given interval using functions.
- C program to print all natural numbers from 1 to n using functions.
- C program to find sum of all natural numbers from 1 to n using functions.
- C program to find reverse of any number using recursion.
- C program to check whether a number is palindrome or not using recursion.

< pre>< code >----Your Source Code---- < / code > < / pre > (Remove spaces from pre and code tags)