Thread: Problem understandnig...pls help

hi everyone, can someone help me explain no what is this code means?

Code:

bool FindNumber(int iPos)
{
    int iNumberTwo, iTotal;

    if(iPos < 1)
    
    return false;
    if (iPos == number)
    {
        iTotal = array[iPos-1] + array[0];
        if (IsPrime(iTotal))
        { 
            for(int j=0; j< number; j++)
            {
                printf("%d ", array[j]);
            }
            printf("\n");
            return true;
        }
        else
        return false;
    }
    
    iNumberTwo = GetNumber(iPos, 0);
    while(iNumberTwo != 0)
    {
        array[iPos] = iNumberTwo;
        iTotal = array[iPos]+array[iPos-1];
        if (IsPrime(iTotal))
        {
//   printf("Now in %d, try %d, and %d is prime\n", iPos, ring[iPos], iTotal);
//   for(int i=0; i¡q =iPos; i++)
//   printf("%d ", ring[i]);
//   printf("\n\n");
            if (FindNumber(iPos+1) == true)
            {
// iPos --
            }      
        }
        iNumberTwo = GetNumber(iPos, iNumberTwo);
    }
    return false;
}

You don't understand ANY of it???? Take a look at the tutorials, especially the tutorials covering if-statments, loops, and functions.

I could comment every line... but I don't have the time right now. And, it's going to be hard to understand if you don't already know what an array is, or what a function is.

It's a single function, not a complete program. It calls at least two other functions which are not defined here: IsPrime() and GetNumber().

Also, printf() is unusual in C++. (It's a C function.)

ok thank you for replying, i understand those. and this is the whole program...

Code:

// Problem A: Prime Ring

#include <stdio.h>
#include <iostream>
#include <cstdlib>
#include <math.h>
using namespace std;

bool NotInRing(int iPos, int iNum);
int GetNumber(int iPos, int iNumber);
bool IsPrime(int iNum);
bool FindNumber(int iPos);

int ring[16];
int m;

int main()
{
    int  i, j, k;
//  insert the 1 value into first position which is ring[0]
    ring[0] = 1;

    while (scanf("%d", &m))
    {
        if (m == 0)
        break;

//  printf("Get %d\n", m);
        if (FindNumber(1) == true)
        {
            for(j=0; j<m; j++)
            {
                printf("%d ", ring[j]);
            }
            printf("\n");
        }
    }// end while.
    system("pause");
    return 0;
}

bool NotInRing(int iPos, int iNum)
{
    for(int i=0; i<iPos; i++)
    {
        if (iNum == ring[i])
        {
            return false;
        }
    }
    return true;
}

int GetNumber(int iPos, int iNumber)
{
    for(int i=iNumber+1; i<=m; i++)
    {
        if (NotInRing(iPos, i))
        return i;
    }
    return 0;  
}

bool IsPrime(int iNum)
{
    for (int i=2; i<=sqrt((double)iNum); i++) //sqr/sqrt 
    {
        if (iNum == ((int)iNum/i)*i)		// (inum%i == 0)
        return false;
    }
    return true;
}


bool FindNumber(int iPos)
{
    int iNumberTwo, iTotal;
    
    if(iPos < 1)
    
    return false;

    if (iPos == m)
    {
        iTotal = ring[iPos-1] + ring[0];
        if (IsPrime(iTotal))
        {
            for(int j=0; j< m; j++)
            {
                printf("%d ", ring[j]);
            }
            printf("\n");
            return true;
        }
        else
        return false;
    }
    
    iNumberTwo = GetNumber(iPos, 0);
    while(iNumberTwo != 0)
    {
        ring[iPos] = iNumberTwo;
        iTotal = ring[iPos]+ring[iPos-1];
        if (IsPrime(iTotal))
        {
//   printf("Now in %d, try %d, and %d is prime\n", iPos, ring[iPos], iTotal);
//   for(int i=0; i¡q =iPos; i++)
//   printf("%d ", ring[i]);
//   printf("\n\n");
            if (FindNumber(iPos+1) == true)
            {
// iPos --;
            }      
        }
        iNumberTwo = GetNumber(iPos, iNumberTwo);
    }
    return false;
}

this program works perfect for me , and this is exactly what i want but wat do you mean printf() is for c?

if it is for c, and what is in c++?

thank you.

actually i already work it out. but still need to thank you for all who participate and helps.

what is this code mean which is in the FindNumber function?

Code:

 if(iPos < 1)
    
    return false;
    if (iPos == number)

by wat i think for the IPOS, i think is i position...
well that is just wat i guess..

not really sure....

That's a check for valid input. The function expects iPos (passed in by the function's caller) to be >= 1. If it's not, the function bails out rather than running with bad data.