Given a number n, find how many n digit number can be formed that does not contain 9 as it’s digit.
Examples:
Input : 1 Output : 8 Explanation : Except 9, all numbers are possible Input : 2 Output : 72 Explanation : Except numbers from 90 - 99 and all two digit numbers that does not end with 9 are possible.
Total numbers of n digit number that can be formed will be 9*10^(n-1) as except first position all digits can be filled with 10 numbers (0-9). If a digit 9 is eliminated from the list then total number of n digit number will be 8*9^(n-1).
Below is the implementation of above idea:
C++
// CPP program to find number of n // digit numbers that do not // contain 9 as it's digit #include <bits/stdc++.h> using namespace std; // function to find number of // n digit numbers possible int totalNumber(int n) { return 8*pow(9, n - 1); } // driver function int main() { int n = 3; cout << totalNumber(n); return 0; } |
Java
// Java program to find number of // n digit numbers that do not // contain 9 as it's digit import java.io.*; public class GFG { // function to find number of // n digit numbers possible static int totalNumber(int n) { return 8 * (int)Math.pow(9, n - 1); } // Driver Code static public void main (String[] args) { int n = 3; System.out.println(totalNumber(n)); } } // This code is contributed by vt_m. |
Python3
# python program to find number of n # digit numbers that do not # contain 9 as it's digit # function to find number of # n digit numbers possible def totalNumber(n): return 8 * pow(9, n - 1); # driver function n = 3print(totalNumber(n)) # This code is contributed by Sam007 |
C#
// C# program to find number of // n digit numbers that do not // contain 9 as it's digit using System; public class GFG { // function to find number of // n digit numbers possible static int totalNumber(int n) { return 8 * (int)Math.Pow(9, n - 1); } // Driver Code static public void Main () { int n = 3; Console.WriteLine(totalNumber(n)); } } // This code is contributed by vt_m. |
php
<?php // php program to find number of n // digit numbers that do not // contain 9 as it's digit // function to find number of // n digit numbers possible function totalNumber($n) { return 8 * pow(9, $n - 1); } // driver function $n = 3; print(totalNumber($n)) // This code is contributed by Sam007 ?> |
Output:
648
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