纪念逝去的岁月——C/C++二分查找

代码

#include <stdio.h>

int binarySearch(int iList[], int iNum, int iX, int * pPos)
{
    if(NULL == pPos)
    {
        return -;
    }
    int i = , j = iNum;
    while(i < j)
    {
        printf("from [%d] to [%d]\n", i, j);
        int iPos = (i + j) / ;
        int iMid = iList[iPos];
        if(iX == iMid)
        {
            *pPos = iPos;
            return ;
        }
        else if (iX > iMid)
        {
            i = iPos + ;
        }
        else
        {
            j = iPos - ;
        }
    }
    if(iList[i] == iX)
    {
        *pPos = i;
        return ;
    }
    *pPos = -;
    return -;
}

int main(int argc ,char * argv[])
{
    int iList[] = {, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , };
    int iPos = ;
    int iNum = ;

    int iX = ;
    binarySearch(iList, iNum, iX, &iPos);
    printf("[%d] @ position [%d]\n\n", iX, iPos);

    iX = ;
    binarySearch(iList, iNum, iX, &iPos);
    printf("[%d] @ position [%d]\n\n", iX, iPos);

    iX = ;
    binarySearch(iList, iNum, iX, &iPos);
    printf("[%d] @ position [%d]\n\n", iX, iPos);

    iX = ;
    binarySearch(iList, iNum, iX, &iPos);
    printf("[%d] @ position [%d]\n\n", iX, iPos);

    iX = -;
    binarySearch(iList, iNum, iX, &iPos);
    printf("[%d] @ position [%d]\n\n", iX, iPos);

    iX = ;
    binarySearch(iList, iNum, iX, &iPos);
    printf("[%d] @ position [%d]\n\n", iX, iPos);

    return ;
}

编译

$ g++ -o binarySearch binarySearch.cpp

运行

$ ./binarySearch
from [] to []
from [] to []
from [] to []
from [] to []
[] @ position []

from [] to []
from [] to []
from [] to []
from [] to []
[] @ position [-]

from [] to []
from [] to []
from [] to []
from [] to []
[] @ position []

from [] to []
from [] to []
from [] to []
from [] to []
from [] to []
[] @ position []

from [] to []
from [] to []
from [] to []
from [] to []
[-] @ position [-]

from [] to []
from [] to []
from [] to []
from [] to []
from [] to []
[] @ position [-]

再见……