C语言二分查找（折半查找）

二分查找是顺序查找中的一种，二分查找的前提是查找表中的数据必须是有序的。

#include 
#define MaxSize 10
typedef struct {
	char key[MaxSize];
	int length;
} SqList;
int Init(SqList *q){
	q->length = MaxSize;
	for(int i = 0; i < q->length; i++) scanf("%c", &q->key[i]);
	return 0;
}
int Seach(SqList *q, char e){
	int low, high, mid;
	low = 0;
	high = q->length-1;
	while(low <= high){
		mid = (low + high)/2;
		if(q->key[mid] == e){
			printf("you want screach '%c'in %dn", e, mid+1);
			return mid;
		}
		else if(q->key[mid] > e) high = mid - 1;
		else low = mid + 1;
	}
	printf("sorry!!!");
	return 0;
}
int main(void){
	SqList q;
	printf("begin init please input 10 number:n");
	Init(&q);
	char e;
	printf("init end!,please input you want search number:");
	getchar();
	e = getchar();
	Seach(&q, e);
	return 0;
}

【运行结果】