# C program to find cube of a number using function

Write a C program to input any number from user and find cube of the given number using function. How to find cube of a given number using function in C programming. Write a C function to find cube of a given number.

Example

Input

`Input any number: 5`

Output

`Cube of 5 = 125`

## Required knowledge

Must know - Program to find power of two number.

## Declare function to find cube of a number

Cube of a number num is `cube = num * num * num`. This is easy, but we need to write a separate function for this simple statement.

1. First assign a meaningful name to the function, say `cube()`.
2. The function should accept a number whose cube is to be calculated. Hence, function definition is `cube(double num)`.
3. Finally, the function should return cube of num passed. Hence, return type of function should be `double`.

After observing above points function declaration looks like `double cube(double num);`

Note: Instead of taking `double` as parameter and return type. You can also use `int`, `float` or any other integer/fractional types. However, `double` fits best for the above requirement.

## Program to find cube using function

``````/**
* C program to find cube of any number using function
*/
#include <stdio.h>

/* Function declaration */
double cube(double num);

int main()
{
int num;
double c;

/* Input number to find cube from user */
printf("Enter any number: ");
scanf("%d", &num);

c = cube(num);

printf("Cube of %d is %.2f", num, c);

return 0;
}

/**
* Function to find cube of any number
*/
double cube(double num)
{
return (num * num * num);
}
``````

Important note: Inside `cube()` function you can also use a temporary variable to store cube of num. Which is

``````double cube(double num)
{
double c = num * num * num;
return c;
}``````

However, the above approach is not worth. In addition, it increases complexity to declare a useless variable c. Instead we can directly return cube of num as in first approach.

`%.2f` prints fractional numbers up to 2 decimal places. You can also use `%f`, to print fractional numbers up to 6 decimal places (default).

Output

```Enter any number: 5
Cube of 5 is 125.00```

Happy coding 😉 