Mega Code Archive
Use predicate, which returns whether an integer is a prime number, with a list
<![CDATA[
/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <list>
#include <algorithm>
#include <cstdlib> // for abs()
using namespace std;
// predicate, which returns whether an integer is a prime number
bool isPrime (int number)
{
// ignore negative sign
number = abs(number);
// 0 and 1 are no prime numbers
if (number == 0 || number == 1) {
return false;
}
// find divisor that divides without a remainder
int divisor;
for (divisor = number/2; numberdivisor != 0; --divisor) {
;
}
// if no divisor greater than 1 is found, it is a prime number
return divisor == 1;
}
int main()
{
list<int> coll;
// insert elements from 24 to 30
for (int i=24; i<=30; ++i) {
coll.push_back(i);
}
// search for prime number
list<int>::iterator pos;
pos = find_if (coll.begin(), coll.end(), // range
isPrime); // predicate
if (pos != coll.end()) {
// found
cout << *pos << " is first prime number found" << endl;
}
else {
// not found
cout << "no prime number found" << endl;
}
}
29 is first prime number found
]]>