大开销递归版二分查找

#include <stdio.h>
#include <time.h>

#define SIZE 20

void print_array(int a[], int len)
{
int i = 0;
for (i = 0; i < len; i++){
printf("%d,", a[i]);
}
printf("\n");
}
void swap(int a[], int i, int j)
{
int temp = a[i];
a[i] = a[j];
a[j] = temp;
}

void selection_sort(int a[],int len)
{
int i = 0;
int j = 0;
for (i = 0; i < len; i++){
for (j = i; j < len;j++){
if (a[j] < a[i]){
swap(a,i,j);
}
}
}
}
int binary_search(int a[],int low, int high, int key)
{
int ret = -1;

if (low <= high){
int mid = (low + high) / 2;
if (a[mid] == key){
ret = mid;
}
else if (a[mid] > key){
ret = binary_search(a,low,mid-1,key);
}
else{
ret = binary_search(a, mid+1, high, key);
}
}

return ret;
}

int main(void){
int a[SIZE] = { 0 };
int i = 0;
int key = 0;
int index = -1;

srand((unsigned int)time(NULL));

for (i = 0; i < SIZE; i++){
a[i] = rand() % 100;
}

key = rand() & 100;

printf("Static Search Demo\n");
printf("Key: %d\n", key);
printf("Array: \n");
print_array(a, SIZE);
selection_sort(a,SIZE);
print_array(a, SIZE);
index = binary_search(a, 0,SIZE, key);
if (index >= 0){
printf("SUCCED: a[%d] = %d\n", index, a[index]);
}
else{
printf("Failed!!\n");
}

system("PAUSE");
return 0;
}