Project Euler Forum

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#initial variables
#print "This program computes the highest prime number of whatever interger suits your fancy."
#startingNumber = testingNumber = 13195  #(correct)
#startingNumber = testingNumber = ((600851475143+13195)/2)
startingNumber = testingNumber = (600851475143)
primePossibles = []

print "Starting", startingNumber

#use loop to find factors, store to list
while testingNumber >= 1:
    if startingNumber % testingNumber == 0:
        primePossibles.append(testingNumber % startingNumber)
        testingNumber = testingNumber - 1
        print primePossibles
    else:
        testingNumber = testingNumber - 1
        
print "Numbers to be tested", primePossibles

#determine which numbers are prime
testNumber = len(primePossibles) - 1 #works

while testNumber >= 0:
    pTest = 2
    print "the number being tested is ", primePossibles[testNumber], "at position ", testNumber
    #print "the first dividend wish start at", pTest
    while pTest < primePossibles[testNumber]:
        if primePossibles[testNumber] % pTest == 0: #doesnt have a remainder
            primePossibles.pop(testNumber)#pop it
            pTest = primePossibles[testNumber]
            #print "Does Have a Remainder, means it's not prime"
            #print primePossibles[testNumber]
            #print pTest
            #print
        else: #has a remainder
            pTest = pTest + 1
            #print "Doesnt Have a Remainder, next try"
            #print primePossibles[testNumber]
            #print pTest
            #print
    #print "end of prime test for", primePossibles[testNumber]
    testNumber = testNumber - 1  
    #print primePossibles
#use loop to determine largest of the prime numbers, use for loop to go through list
print primePossibles[1]

Code: Select all

/*
Project Euler Problem 3 - I can produce all factors of a number; but it
stops working when I go for the prime number

Also, large numbers murders it.
*/
#include <cstdio>
#include <cstdlib>
#include <iostream>
using namespace std;

int main(int nNumberofArgs, char* pszArgs[])
{
    int x = 1;
    int a = 2;
    long long limit = 13195LL;
    long long factor = 0LL;
    int prime = 0;

    for (;x <= limit; x++)
    {
      factor = limit % x;
      if (factor == 0)
      {
        cout << x
             << " is a factor of "
             << limit
             << "."
             << endl;
        
      }
    }
       
    //wait until user is ready before terminating program
    //to allow the user to see the program results
    system ("pause");
    return 0;
}    

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