Count numbers from 1 to n that have 4 as a digit in C++

C++Server Side ProgrammingProgramming

In this tutorial, we will be discussing a program to find the numbers from 1 to n that have 4 as a digit.

For this we will be provided with a number n. Our task is to count all the numbers which have 4 as one of their digits and print it out.

Example

Live Demo

#include<iostream>
using namespace std;
bool has4(int x);
//returning sum of digits in the given numbers
int get_4(int n){
int result = 0;
//calculating the sum of each digit
for (int x=1; x<=n; x++)
result += has4(x)? 1 : 0;
return result;
}
//checking if 4 is present as a digit
bool has4(int x) {
while (x != 0) {
if (x%10 == 4)
return true;
x = x /10;
}
return false;
}
int main(){
int n = 328;
cout << "Count of numbers from 1 to " << n
<< " that have 4 as a digit is "
<< get_4(n) << endl;
return 0;
}

Output

Count of numbers from 1 to 328 that have 4 as a digit is 60
Published on 05-Feb-2020 07:57:20