first numbers and structs

#include <iostream>

#include <stdio.h>
#define max 100

using namespace std;



bool is_first(int x)
{
    int i,sum;
    sum=0;
    for(i=1;i<x+1;i++)
     if(x%i==0)
       ++sum;
    if(sum==2)
     return true;
    else
     return false;
}
int how_many_first(int first)
{
    int i,sum;
    sum=0;
    for(i=1;i<first;i++)
     if(is_first(i))
      ++sum;
    return sum;
}
int sum_first(int first)
{
    int i,sum;
    sum=0;
    for(i=1;i<first;i++)
     if(is_first(i))
      sum+=i;
    return sum;
}
double down_zero(double x, double y)
{
    double z;
    if(x<y)
     z=x/y;
    else
     z=y/x;
    return z;
   
}
double up_zero(double x, double y)
{
    double z;
    if(x>y)
    z=x/y;
    else
    z=y/x;
    return z;
}
double div_value(double x, double y)
{
    return x/y;
}
double one_value(double x, double y)
{
    return up_zero(x,y)*down_zero(x,y);
}
int *tab_first;
int *temp_tab;
struct first_functions
{
    int size;
    int  div_sum;
    double up_first;
    double down_first;
};
struct result
{
    double one_zero;
    int how_many;
    int m_sum;
};

int main(int argc, char **argv)
{
   
    tab_first=new int[max];
    temp_tab=new int[max];
    struct first_functions *first_fun=new struct first_functions[max];
    struct result *first_result=new struct result[max];
    int i,j;
    i=0;
    j=0;
    do
    {
        if(is_first(j))
        {
            tab_first[i]=j;
            ++i;
        }
        ++j;
    }while(i<max);
    for(i=0;i<max;i++)
    {
        first_fun[i].size=how_many_first(tab_first[i]);
        first_fun[i].div_sum=sum_first(tab_first[i]);
       
       
    }
    double temp1[max];
    for(j=0;j<max;j++)
    {
        temp1[j]=1.0*tab_first[j];
    }
    for(i=1;i<max+1;i++)
    {
        first_fun[i-1].down_first=down_zero(temp1[i-1],temp1[i]);
        first_fun[i-1].up_first=up_zero(temp1[i-1],temp1[i]);
    }
   
    for(i=0;i<max;i++)
    {
        first_result[i].one_zero=one_value(first_fun[i].down_first,first_fun[i].up_first)*
        one_value(1.*first_fun[i].div_sum,div_value(1.,first_fun[i].div_sum))*
        one_value(1.*first_fun[i].size,div_value(1.,first_fun[i].size))*
        tab_first[i];
        first_result[i].how_many=first_fun[i].size;
        first_result[i].m_sum=first_fun[i].div_sum;
        cout<<first_result[i].one_zero<<"    "<<first_result[i].how_many<<"   "<<first_result[i].m_sum<<endl;       
       
    }
   
   
    delete temp_tab;
    delete first_result;
    delete first_fun;
    delete tab_first;
    return 0;
}