/**********************************************************************
	A simple sort program. 
	A real program should use C++ standard library algorithm 'sort'.
	C.A. Bertulani, May/19/2000 	
**********************************************************************/

#include <stdio.h>
#include <malloc.h>
#include <iostream.h>
#include <string.h>
typedef int (*CFT) (const void*, const void*);

/**********************************************************************
	Sort the "n" elements of vector "base" into increasing 
	order using the comparison fucntion pointed t by "cmp".
	The elements are of size "sz.
	Shell sortKnuth, Vol3, p. 84)
***********************************************************************/
void ssort (void* base, size_t n, size_t sz, CFT cmp)
{
	for (unsigned int gap=n/2; 0<gap; gap/=2)
		for (unsigned int i=gap; i<n; i++)
			for (int j=i-gap;0<=j;j-=gap) {
				char*b =static_cast<char*>(base);  //necessary cast
				char* pj =b+j*sz;				// &base[j]
				char*pjg =b+(j+gap)*sz;			//&base[j+gap]
				
				if (cmp(pjg,pj)<0) {			// swap base[j] and base[j+gap];
					for (unsigned int k=0; k<sz; k++) {
						char temp = pj[k];
						pj[k] = pjg[k];
						pjg[k] = temp;
					}
				}
			}
}
/**********************************************************************
	Define known information about users
***********************************************************************/
struct User{
	char* name;
	char* id;
	int acct;
};
/**********************************************************************
	Define physicists and their related information
***********************************************************************/
User physicist[]={
		"Souza S.R.", "srs", 1171,
		"Donangelo R.", "rd", 1175,
		"Canto L.F.", "lfc", 1173,
		"Bertulani C.A.", "cab", 1174,
		"Kodama T.", "tk", 1176,
		"Aguiar C.E.", "cea", 1176,
		"Aleixo A.N.F.", "anfa", 1175,
		"Fereira E.M.", "emf", 1172
};
/**********************************************************************
	Prints information
***********************************************************************/
void print_id (User* v, int n)
{
	for (int i=0;i<n;i++)
		cout << v[i].name << '\t' << v[i].id << '\t'<< v[i].acct << '\n';
}
/**********************************************************************
	Compare information
***********************************************************************/
int cmp1 (const void* p, const void* q)	// compare name strings
{
	return strcmp(static_cast<const User*>(p)->name, static_cast<const User*>(q)->name);
}

int cmp2 (const void* p, const void* q)	// compare acct numbers
{
	return static_cast<const User*>(p)->acct - static_cast<const User*>(q)->acct;
}
/**********************************************************************
	Order physicists as you wish
***********************************************************************/
int main()
{
	int k = 8;
	void ssort (void* , size_t , size_t, CFT);
	cout << "Physicist in alphabetical order:\n";
	ssort(physicist,k,sizeof(User),cmp1);
	print_id(physicist,k);
	cout<<'\n';
	cout<<"Physicist in order of account number:\n";
		ssort (physicist,k,sizeof(User),cmp2);
	print_id(physicist,k);
	return 0;
}
/***********************************************************************/