# include # include using namespace std; int main ( int argc, char *argv[] ); //****************************************************************************80 int main ( int argc, char *argv[] ) //****************************************************************************80 // // Purpose: // // MAIN is the main program for PRIME_SUM. // // Discussion: // // PRIME_SUM adds up the prime numbers from 2 to N. // // Invoke the program with a command like // // prime_sum n // // The sum is printed out. // // Example: // // prime_sum 10 = 17 = 2 + 3 + 5 + 7 // prime_sum 100 = 1060 // prime_sum 1000 = 76127 // prime_sum 10000 = 5736396 // // Licensing: // // This code is distributed under the GNU LGPL license. // // Modified: // // 01 April 2008 // // Author: // // John Burkardt // { int i; int j; int n; bool prime; int total; // // If called with no arguments, use N = 100. // if ( argc < 1 ) { n = 100; } else { *argv++; n = atoi ( *argv ); } total = 0; // // Consider each integer I from 2 to N. // for ( i = 2; i <= n; i++ ) { // // Determine if I is prime. // prime = true; for ( j = 2; j < i; j++ ) { if ( i % j == 0 ) { prime = false; break; } } // // If prime, add to sum. // if ( prime ) { total = total + i; } } // // Print the sum. // cout << "PRIME_SUM(2:" << n << ") = " << total << "\n"; return 0; }