折半查找，输出位置，代码错误

Question

#include<stdio.h>

int main()
{
    int a[15],i,j,flag = 0,num,mid;
    printf("Please input 15 number:");
    a[15]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
    printf("\nPlease input a number:");
    scanf("%d",num);
    i = 0;
    j = 14;
    while(i<=j)
    {
        mid = (i+j)/2;
        if(a[mid] ==num)
        {
            printf("该数是第%d个元素",mid+1);
            flag = 1;
            break;
        }
        if(num<a[mid])
            j = mid-1;
        if(num>a[mid])
            i = mid+1;
    
    }
    if(flag == 0)
        printf("无此数！");
    return 0;
}

Answer 1

• 数组元素初始化，不能像你那样，需要在定义的时候初始化

int a[15]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
// 要么你就用循环自己输入
for(i=0;i<15;i++)
        scanf("%d", &a[i]);

• 下面输入，需要取地址符&，改成 如下：

scanf("%d",&num);