c - 如果找不到数字，如何使这个递归二分查找程序退出而不崩溃？

Question

如果找不到用户搜索的值，如何防止程序崩溃？ (当我尝试实现 if/else 或计数系统时，程序无法正常工作)

#include <stdio.h>
#include "simpio.h"
#include "genlib.h"
#define start 0
void bubble(int numbers[]);
int binary(int val, int numbers[], int low, int high);
void io(int numbers[]);
int size;
main()
{
    int result, search;
    printf("This program sorts and searches an array\n");
    printf("How many numbers would you like to sort and search?\n");
    size = GetInteger()-1;
    int numbers[size];
    printf("Enter the numbers\n");
    io(numbers);
    bubble(numbers);
    printf("Which number would you like to search for?\n");
    search = GetInteger();
    result = binary(search,numbers,start,size);
    printf("The number %d was found at index %d\n",search,result+1);
}

void io(int numbers[])
{
    int ink;
    for(ink=0;ink<=size;ink++)
    {
        numbers[ink] = GetInteger();
    }
}

void bubble(int numbers[])
{
    int first,second,count,swap;
    while(TRUE)
    {
        for(first=0,second=1,count=0;second<=size;first++,second++)
        {
            if(numbers[first]>numbers[second])
            {
                count++;
                swap = numbers[first];
                numbers[first]= numbers[second];
                numbers[second] = swap;
            }
        }
        if(count==0)break;
    }
}

int binary(int val, int numbers[], int low, int high)
{
    int mid;
    mid = (low+high)/2;
    if(val==numbers[mid]||low>high) return mid;
    if(val>numbers[mid]) return(binary(val,numbers,mid,high));
    else if(val<numbers[mid]) return(binary(val,numbers,low,mid));
}

Answer 1

更改为

size = GetInteger();
int numbers[size--];//change size to max index
//..

int binary(int val, int numbers[], int low, int high)
{
    int mid;
    if(low>high)//if not found!
        return -1;//check return value at main
    mid = (low+high)/2;
    if(val==numbers[mid]) return mid;
    if(val>numbers[mid]) return(binary(val,numbers,mid+1,high));
    else if(val<numbers[mid]) return(binary(val,numbers,low,mid-1));
}