code help

[ghostrider_gr]

next one: i have found alla the primes (previous topic) and now i want in a list all the numbers (p^2^k)<=Upper limit where p the prime, k a nonnegative integer.. for example if upper limit is 24 then i want :

[2,2^2=4,2^3=8,16,3,9,5,7,11,13,17,23]

Code: Select all

    #include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    
    #define UPPER_LIMIT 42
    #define B 5

    typedef struct primes_ {
       int no;
       struct primes_ * next;
    } PrimesList;


    int main (){

       int i,count, flag1;
       PrimesList *list, *temp, *initial;

       list = (PrimesList*)malloc(sizeof(PrimesList));
       list->no = 2;
       list->next = NULL;
       temp = list;

       count = 1;

       i = 3;

       while (i <= B) {

          initial = list;
          flag1 = 0;

          while ( ((initial->next) != NULL) && (flag1 == 0) ) {
             if ((i % initial->no) == 0){
                flag1 = 1; // prime factor exists -> skip this number
             }
             else{
                initial = initial->next; // advance to next prime
             }
          }

          if (flag1 == 0) {
             temp->next = (PrimesList*)malloc(sizeof(PrimesList));
             temp = temp->next;
             temp->no = i;
             temp->next = NULL;
             count++;
          }
          i += 2;
       }

    temp = list;
       
    PrimesList *listS, *tempS;
    listS=(PrimesList*)malloc(sizeof(PrimesList));
    tempS=listS;
    
    tempS->no=1;
    tempS->next=(PrimesList*)malloc(sizeof(PrimesList));
    tempS=tempS->next;
    tempS->next=NULL;
    
    while (temp->next !=NULL) {
          int p=temp->no;
          int k=0,flagS=0;
          while (flagS==0) {
                int z=pow(p,2);
                if ((pow(z,k)) <= (UPPER_LIMIT)) {
                   tempS->no=pow(z,k);
                   tempS->next=(PrimesList*)malloc(sizeof(PrimesList));
                   tempS=tempS->next;
                   tempS->next=NULL;
                }
                else  flagS=1;
                k=k+1;
          }
          temp=temp->next;
    }
    temp=list;
    tempS=listS;
       
       while (tempS != NULL) {
          printf("%d next: \n ",tempS->no);
          tempS = tempS->next;
       }

       system("pause");
       //getchar();
       return 0;
    }

it doesn't print me all the numbers..

[Neo]

The sequence looks like p^(2+k) < UPPER_LIMIT where k = -1, 0, 1, 2, 3, ...... N

If you take the first prime number on the list.. i.e.: 2

k = -1, 2^(2+(-1)) = 2¹ = 2 ? Save same number to the list
k = 0, 2^{(2+( 0))} = 2² = 4
k = 1, 2^{(2+( 1))} = 2³ = 8
k = 2, 2^{(2+( 2))} = 2⁴ = 16
k = 3, 2^{(2+( 3))} = 2⁵ = 32 (We will not save this number as UPPER_LIMIT = 24)

So our list for 2 is, 2, 4, 8, 16

k = -1, 3^(2+(-1)) = 3¹ = 3 ? Save same number to the list
k = 0, 3^{(2+( 0))} = 3² = 9
k = 1, 3^{(2+( 1))} = 3³ = 27 (We will not save this number as UPPER_LIMIT = 24)

So the next list would be 3, 9

and so on for 5, 7, 11, 13, 17, 23

Can you confirm this?

[ghostrider_gr]

The sequence looks like p^(2+k) < UPPER_LIMIT where k = -1, 0, 1, 2, 3, ...... N

If you take the first prime number on the list.. i.e.: 2

k = -1, 2^(2+(-1)) = 2¹ = 2 ? Save same number to the list
k = 0, 2^{(2+( 0))} = 2² = 4
k = 1, 2^{(2+( 1))} = 2³ = 8
k = 2, 2^{(2+( 2))} = 2⁴ = 16
k = 3, 2^{(2+( 3))} = 2⁵ = 32 (We will not save this number as UPPER_LIMIT = 24)

So our list for 2 is, 2, 4, 8, 16

k = -1, 3^(2+(-1)) = 3¹ = 3 ? Save same number to the list
k = 0, 3^{(2+( 0))} = 3² = 9
k = 1, 3^{(2+( 1))} = 3³ = 27 (We will not save this number as UPPER_LIMIT = 24)

So the next list would be 3, 9

and so on for 5, 7, 11, 13, 17, 23

Can you confirm this?

thanks for your help... i solved it.. i constructed power because i couldn;t handle pow.. and its ok now..

next one because this one drives me crazy..

this is part of my code...

Code: Select all

printf("%d\n",listS->no);//right print
       printf("%d\n",listS->next->no);//right print
       printf("%d",tempS->no);//right
       system("pause");


 printf("%d",listS->no);//false

i mean "listS->no" doesn't change..why it prints me false results.. it prints something irrelevent and then i get a message..".exe has stopped working"..

[Neo]

It sounds like listS is NULL.

[ghostrider_gr]

It sounds like listS is NULL.

yes but in the first printf i get the right result... i mean its like my programm doesn't work from that point..

[Neo]

It is not good to do something like list->next->no when you don't know that list->next is not NULL. This might corrupt the memory. So before printing, make sure, you check list->next != NULL.