机试算法讲解：第2题 结构体之快速排序

/*
题目:
学生成绩排序：成绩从低到高，姓名字母从低到高（区分大小写），年龄从低到高排序
输入:
3
abc 20 99
bcd 19 97
bed 20 97

输出:
bcd 19 97
bed 20 97
abc 20 99

易错点:
1对于字符指针，scanf("%s",ps[i].sName)不需要取地址符
2对于名字，要指定大小，否则内存访问非法,char sName[128];而不是定义char* sName;
3int strcmp(const char* string1,const char* string2); <0:前<后

得分:0
*/

#include <stdio.h>
#include <malloc.h>
#include <string.h>

typedef struct Student
{
	//Student(char* name,int age,int grade):sName(name),iAge(age),iGrade(grade){}
	//char* sName;//就是这里出错了，没有具体制定多大
	//char* sName;

	//法二，用重载操作符operator<的方法做
	bool operator < (const Student& stu) const
	{
		if(iGrade != stu.iGrade)
		{
			return iGrade < stu.iGrade;
		}
		else
		{
			if(sName != stu.sName)
			{
				return strcmp(sName,stu.sName) < 0 ? true:false;
			}
			else
			{
				return iAge < stu.iAge;
			}
		}
	}
	char sName[128];
	int iAge;
	int iGrade;
}Student;

bool compare(struct Student stuA,struct Student stuB)
{
	if(stuA.iGrade < stuB.iGrade)
	{
		return true;
	}
	else if(stuA.iGrade == stuB.iGrade )
	{
		if(stuA.sName!=stuB.sName)
		{
			return strcmp(stuA.sName,stuB.sName) < 0 ? true:false ;//这里中断了
		}
		else
		{
			return stuA.iAge < stuB.iAge;
		}
	}
	else
	{
		return false;
	}
}

int partition(Student* ps,int low,int high)
{
	Student stu = ps[low];
	while(low < high)
	{
		//while(low < high && compare(stu,ps[high]))//法1
		while(low < high && stu < ps[high])
		{
			high--;
		}
		ps[low] = ps[high];
		//while(low < high && compare(ps[low],stu))//法1
		while(low < high && ps[low] < stu)
		{
			low++;
		}
		ps[high] = ps[low];
	}
	ps[low] = stu;
	return low;
}

void quickSort(Student* ps,int low,int high)
{
	if(low < high)
	{
		int iPos = partition(ps,low,high);
		quickSort(ps,low,iPos-1);
		quickSort(ps,iPos+1,high);
	}
}

void print(Student* ps,int iNum)
{
	for(int i = 0;i < iNum ;i++)
	{
		printf("%s %d %d\n",ps[i].sName,ps[i].iAge,ps[i].iGrade);
	}
}

int main(int argc,char* argv[])
{
	int iNum;
	while(EOF!=scanf("%d",&iNum))
	{
		//ptrStu ps = (ptrStu)malloc(iNum*sizeof(Student));
		Student* ps = (Student*)malloc(iNum*sizeof(Student));
		//Student ps[100];
		for(int i = 0; i < iNum; i++)
		{
			//char* sName;
			//int iAge,iGrade;
			//scanf("%s %d %d",&ps[i].sName,&ps[i].iAge,&ps[i].iGrade);	//关键字符串不需要取地址，因为它本身就是一个地址，否则就是取地址的地址了
			scanf("%s %d %d",ps[i].sName,&ps[i].iAge,&ps[i].iGrade);
			//Student *stu = (Student*)malloc(1*sizeof(Student))(sName,iAge,iGrade);
			//ps[i] = stu;//难道是因为出了这里就不存在了
		}
		//printf("%s\n",ps[1].sName);
		//print(ps,iNum);
		quickSort(ps,0,iNum-1);
		print(ps,iNum);
		free(ps);
	}
	//getchar();
	return 0;
}