在相邻元素相差1的数组中查找某一特定元素第一次出现的位置

题目：数组中相邻的每两个数之间的差值是1或-1，给定一个数N，求如何找到第一个N的位置。

如：3,4,3,2,1,2,3,4,3,4,5,6,5   求第一个5所在的位置。

#include <stdio.h>

#include <stdlib.h>



int main(void)

{

    int a[] = {3,4,3,2,1,2,3,4,3,4,5,6,5};

    int i, next, to_search;

    int len = sizeof(a);

    int count = 0, found = 0;



    printf("Please input the number that you want to search: ");

    scanf("%d",&to_search);



    for( i=0; i<len; i+=next)

    {

        ++count;

        if( a[i] == to_search )

        {

            found = 1;

            break;

        }

        else

            next = abs(a[i]-to_search);

    }

    printf("Search times: %d\n",count);

    if( found )

        printf("%d is at a[%d]\n",to_search, i);

    else

        printf("Not found.\n");



    return 0;

}