décimal vers hexa

//#include <cstdio>
//#include <cstdlib>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <math.h>

using namespace std;

const int oct=2;
char cbinaire(int ix,FILE* file)
{

//if i=
char binary[9*(::oct)]={0};

for(int i=8*::oct;i>0;i-
{
double ix2=ix/pow(2,i)-floor(ix/pow(2,i));
if (ix2<0.5)
{
strcat(binary, "O");
}
else// if (ix/pow(2,i)>=0.5)
{
strcat(binary, "I");
}
}
fprintf(file,"bin = %s \n",binary);
cout<<"bin = "<< binary<<endl;
//return &binary;
}
int main(int argc,char *argv[])
{
FILE* fichier = NULL;
fichier=fopen("binaire_file.txt","w");

if (fichier == NULL)
{
printf("Impossible d'ouvrir le fichier binaire_file.txt");
system("PAUSE");
return EXIT_FAILURE;
}

char* ext[9*::oct]={0};

for(int i=0;i<pow(256,::oct);i++)
{
fprintf(fichier,"hex = %X \n",i);
cout<<"hex = "<<std::hex<<std::uppercase<< i<<endl;
cbinaire(i,fichier);


}
fclose(fichier);
system("PAUSE");
return EXIT_SUCCESS;
}