Home » Rust » Rust Programs

Rust program to count the digits of a given number using recursion

Rust | Count Digits: Write a program to count the digits of a given number using recursion.
Last Updated : October 10, 2021

Problem Statement

In this program, we will create a recursive function to count the number of digits of a number using recursion and return the result to the calling function.

Program/Source Code

The source code to count the digits of a given number using recursion is given below. The given program is compiled and executed successfully.

// Rust program to count the digits 
// of given number using recursion

unsafe fn CountDigits(num:i32)->i32 {
    static mut count:i32=0;
	if num > 0 {
		count = count + 1;
		CountDigits(num / 10);
	}
	return count;
}

fn main() 
{
    unsafe{
        let res=CountDigits(1234);
        println!("Total digits are: {}",res);
    }
}

Output

Total digits are: 4

Explanation

In the above program, we created two functions CountDigits() and main(). The CountDigits() function is a recursive function, which is used to count the digits of the given number and return the result to the calling function.

In the main() function, we called CountDigits() function and printed the result.

Rust Functions Programs »

---