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昨天大概讲解了一下qsort函数及其简单应用。我们再看一遍qsort函数：
void qsort(void * base, int size, int num, int(*cmp)(void *, void *))；
下面我们用冒泡排序模拟实现一下，如下：
#define _CRT_SECURE_NO_WARNINGS 1#include#include #include //void qsort(void * base, int size, int num, int(*cmp)(void *, void *))struct stu{ char name[20]; int age;};void Swap(char *buf1, char*buf2, int width){ int i = 0; for (i = 0; i < width; i++) { char tmp = *buf1; *buf1 = *buf2; *buf2 = tmp; buf1++; buf2++; }}void Bubble_sort(void * base, int size, int width, int(*cmp)(void *, void *)){ int i = 0, j = 0; for (i = 0; i < size - 1; i++) { for (j = 0; j < size - i - 1; j++) { //强制类型转换为char *类型，用上宽度width,就可以巧妙地转到不同类型的数据 if (cmp_int((char*)base + j*width, (char*)base + (j + 1)*width)>0) { Swap((char*)base + j*width, (char*)base + (j + 1)*width, width); } } }}int cmp_int(const void * e1, const void * e2){ return *((int *)e1) - *((int *)e2);}int cmp_float(const void * e1, const void * e2){ return (int)(*((float *)e1) - *((float *)e2));}int cmp_stu_by_name(const void * e1, const void * e2){ return strcmp(((struct stu *)e1)->name, ((struct stu *)e2)->name);}int cmp_stu_by_age(const void * e1, const void * e2){ return ((struct stu *)e1)->age - ((struct stu *)e1)->age;}void Print1(struct stu s[3]){ int i = 0; for (i = 0; i < 3; i++) printf("%d ", s[i].age); printf("\n");}void test1(){ int arr[] = { 4, 5, 6, 7, 8, 9, 1, 2, 3, 0 }; int sz1 = sizeof(arr) / sizeof(arr[0]); Bubble_sort(arr, sz1, sizeof(arr[0]), cmp_int); int i = 0; for (i = 0; i < 10; i++) printf("%d ", arr[i]); printf("\n");}void test2(){ float brr[] = { 3.0, 2.0, 4.0, 5.0, 7.0, 4.0 }; int sz2 = sizeof(brr) / sizeof(brr[0]); Bubble_sort(brr, sz2, sizeof(brr[0]), cmp_float); int i = 0; for (i = 0; i < 6; i++) printf("%f ", brr[i]); printf("\n");}void test3(){ struct stu s[3] = { { "zhangsan", 15 }, { "lisi", 23 }, { "wangwu", 8 } }; int sz3 = sizeof(s) / sizeof(s[0]); Bubble_sort(s, sz3, sizeof(s[0]), cmp_stu_by_name); Print1(s);}void test4(){ struct stu s[3] = { { "zhangsan", 15 }, { "lisi", 23 }, { "wangwu", 8 } }; int sz3 = sizeof(s) / sizeof(s[0]); Bubble_sort(s, sz3, sizeof(s[0]), cmp_stu_by_age); Print1(s);}int main(){ test1(); test2(); test3(); test4(); return 0;}
今天就简单说到这了。
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