The Harshad or Niven numbers are positive integers >= 1 that are divisible by the sum of their digits.
For example, 42 is a Harshad number as 42 is divisible by (4+2) without remainder. Assume that the series is defined as the numbers in increasing order.
The task is to create a function/method/procedure to generate successive members of the Harshad sequence. Use it to list the first twenty members of the sequence and list the first Harshad number greater than 1000.
#include <vector> #include <iostream> int sumDigits ( int number ) { int sum = 0 ; while ( number != 0 ) { sum += number % 10 ; number /= 10 ; } return sum ; } bool isHarshad ( int number ) { return number % ( sumDigits ( number ) ) == 0 ; } int main( ) { std::vector<int> harshads ; int i = 0 ; while ( harshads.size( ) != 20 ) { i++ ; if ( isHarshad ( i ) ) harshads.push_back( i ) ; } std::cout << "The first 20 Harshad numbers:\n" ; for ( int number : harshads ) std::cout << number << " " ; std::cout << std::endl ; int start = 1001 ; while ( ! ( isHarshad ( start ) ) ) start++ ; std::cout << "The smallest Harshad number greater than 1000 : " << start << '\n' ; return 0 ; }
- Output:
The first 20 Harshad numbers: 1 2 3 4 5 6 7 8 9 10 12 18 20 21 24 27 30 36 40 42 The smallest Harshad number greater than 1000 : 1002
Content is available under GNU Free Documentation License 1.2.
