hash table

1433531730.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
using namespace std;
#define MAX 50

typedef struct SSTUDENT
{
	char Name[30];
	float Mark;
	struct SSTUDENT *next;
} STUDENT, *PSTUDENT;

int HashFunc(char str[])
{
	int i, n = strlen(str);
	int m = 0;
	for (i = 0; i < n; i++)
		m = (m * 29 + (str[i] - 'A')) % MAX;
	return m;
}

void Add(PSTUDENT HashTable[], STUDENT st)
{
	int key = HashFunc(st.Name);
	PSTUDENT p;
	p = new STUDENT;
	p->Mark = st.Mark;
	strcpy(p->Name, st.Name);
	p->next = NULL;
	p->next = HashTable[key];
	HashTable[key] = p;
}

PSTUDENT Search(PSTUDENT HashTable[], char Name[], PSTUDENT prev)
{
	PSTUDENT p;
	int key = HashFunc(Name); 
	prev = NULL;
	p = HashTable[key];
	while (p != NULL)
	{
		if (strcmp(p->Name, Name) == 0)
		{
			return p;
		}
		prev = p;
		p = p->next;
	}
	return NULL;
}

void Del(PSTUDENT HashTable[], char Name[])
{
	PSTUDENT p, prev;
	p = Search(HashTable, Name, prev);
	if (p != NULL)
		if (prev != NULL)
			prev->next = p->next;
		else
			HashTable[HashFunc(Name)] = p->next;
}

int main()
{
	FILE *src_file;
	PSTUDENT HashTable[MAX];
	STUDENT st;
	char s[15];
	char *pChar;
	int count = 0;

	for (int i = 0; i <MAX; i++)
		HashTable[i] = NULL;

	src_file = fopen("DSSinhvien.txt", "r");
	if (fgets(s,35,src_file)!=NULL)
		count = atoi(s);

	for (int i = 0; i < count;i++)
	{
		if (fgets(s, 35, src_file)!=NULL)
		{
			char tmp[30];
			pChar = strstr(s, "***");
			strncpy(tmp, s, strlen(s) - strlen(pChar));
			tmp[strlen(s) - strlen(pChar)] = '\0';
			strcpy(st.Name, tmp);
			st.Mark = atoi(pChar + 3);
			Add(HashTable, st);
		}
	}
	
	//test add student 
	/*PSTUDENT prev=NULL;
	PSTUDENT search_pstudent = Search(HashTable, "nguyen van a", prev);
	printf("%s \t %f", search_pstudent->Name, search_pstudent->Mark);*/
}