blob: b649a6ae5c7e72a3eafd7f09f9cc1145ef36400c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
// Programmieren 1, Praktikum 2, Aufgabe 4
// Sven Eisenhauer
// 05.11.2004
//
// file: prg1p2_4.cpp
//
// purpose: Program to find all prime numbers, which are smaller than the entered positive number
//
#include <iostream>
#include <iomanip>
using std::cin;
using std::cout;
using std::endl;
int main()
{
int iNumber=0;
int iIsPrime=0;
system ("cls");
cout << "Please enter a positive number: ";
cin >> iNumber;
if (0 >= iNumber) // handle wrong input in some way
{
cout << "Not a positive number!!!";
system ("pause");
}
else // end error handler
{ // let's begin
for (int iOuterCounter=iNumber;iOuterCounter>1;iOuterCounter--)
{ // decrement the number and check, if it is a prime (modulo any number is 0)
iIsPrime=0; // we asume actual number is a prime
for (int iInnerCounter=iOuterCounter-1;iInnerCounter>1;iInnerCounter--)
{
if ( 0 == iOuterCounter%iInnerCounter)
{
iIsPrime=1; // actual number is NOT a prime
}
}// end inner for routine
if (0 == iIsPrime)
cout << endl << iOuterCounter;
} // end outer for routine
cout << endl;
system ("pause"); // wait a moment for user to read
} // end else
return 0;
}// end main
|
