C 语言快速排序算法以及 qsort

c 语言冒泡排序与快速排序示例：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
//快速排序
void quick_sort(float data[], int left, int right){
   int i = left;
   int j = right;
   float tag = data[i];
   while(i<j){
     while( i<j && tag < data[j] ) j--;
     if( i<j ) data[i++] = data[j];
      
     while( i<j && tag > data[i] ) i++;
     if( i<j ) data[j--] = data[i];
   }
   data[i] = tag;
   if( left < i ) quick_sort(data, left, j - 1);
   if( i < right ) quick_sort(data, j + 1, right); 
}
//冒泡排序
void bub_sort(float data[], int n){
  int i,j;
  float tmp;
  for( i = 0; i < n - 1; i++ )
    for( j = 0; j < n - 1 - i; j++)
      if(data[j] > data[j + 1])
      {
         tmp = data[j];
         data[j] = data[j + 1];
         data[j + 1] = tmp;
      }
}
//比较函数
int comp(const void *a, const void *b){
  float x = *(float *)a;
  float y = *(float *)b;

  if( x > y ) return 1;
  else if( x < y ) return -1;
  else return 0;
}

int main(int argc, char *argv[]){
  float data[10], data1[10];
  int i = 0;
  srand((unsigned)time(NULL));

  printf("
 sort data: ");
  for(i = 0; i < 10; i++){//生成随机数
    data[i] = rand() % 100  * 0.1;
    data1[i] = data[i];
    printf("[%.1f] ",data[i]);
  }
  
  quick_sort(data,0, 9);
  qsort(data1, 10, sizeof(float), comp);

  printf("
quick_sort: ");
  for(i = 0; i < 10; i++) printf("[%.1f] ", data[i]);

  printf("
lib  qsort: ");
  for(i = 0; i < 10; i++) printf("[%.1f] ", data1[i]);
  printf("
");

  return 0;
}

运行结果

         sort data: [8.6] [1.2] [5.1] [8.3] [6.5] [4.8] [5.3] [5.3] [7.3] [3.6]
       quick_sort: [1.2] [3.6] [4.8] [5.1] [5.3] [5.3] [6.5] [7.3] [8.3] [8.6]
           lib qsort: [1.2] [3.6] [4.8] [5.1] [5.3] [5.3] [6.5] [7.3] [8.3] [8.6]