#include <stdio.h>
void main()
{
    int bit(int x,int v[],int n);
    int v[]={1,2,3,4,5,6,8,9,12,13,15,18,19,21,24,26,29,36,38,39,40,51,52,53,54,58};
    int x=45,n=26;
    printf("%d",bit(x,v,n));
}
int bit(int x,int v[],int n)
{
    int low=0,high=n-1,mid;
    while(low<=high)
    {
        mid=(low+high)/2;
        if(x<v[mid])
            high=mid-1;
        else if(x>v[mid])
            low=mid+1;
        else
            return mid;
    }
    return -1;
}
此函数是否只能有一个返回值，当 return mid成立了，return -1是否就没用了。