C语言 快速排序函数用法
#include
#include
#include
struct student
{
int id;
char name[12];
char sex;
};
int compare(const void* a,const void* b)//基本数据类型排序
{
return *(char*)a-*(char*)b;//从小到大
//取值//强转为相应类型的指针！！
}
int compare_struct(const void* a,const void* b)
{
return (*(struct student*)a).id-((struct student*)b)->id;
//注意优先级诶！//否则报错在非结构体中。。。
}
int compare_struct_duoji(const void* a,const void* b)//多级排序
{
struct student student_a=*(struct student*)a;
struct student student_b=*(struct student*)b;
if(student_a.id==student_b.id)
{
return student_a.sex-student_b.sex;
}
else
{
return student_a.id-student_b.id;
}
}
void main()
{
//*************char型*************
char a[5]="hello";
qsort(a,5,sizeof(a[0]),compare);
//元素个数//元素大小//函数指针
int i;
for(i=0;i<5;i++)
printf("%c ",a[i]);
printf("\n");
//************struct型************
struct student e[4]={{100,"chen",'m'},{100,"li",'f'}, \
{70,"wang",'f'},{100,"zhang",'m'}};
qsort(e,4,sizeof(e[1]),compare_struct_duoji);
for(i=0;i<4;i++)
printf("%d %s %c\n",e[i].id,e[i].name,e[i].sex);
}
