华为机试题：求车速

#include 
#include 
#include "OJ.h"

/*
功能: 根据里程计算车速
原型：
int CalcSpeedOfCar(int iCurrentMileage, int * piCarSpeed);

输入参数：
int pcCurrentMileage:当前里程数(为对称数)(pcCurrentMileage ≤ 999999)

返回值：
汽车速度(公里/小时)
*/

int CalcSpeedOfCar(int iCurrentMileage, int * piCarSpeed)
{
	/*在这里实现功能*/
	if (iCurrentMileage > 999999)
	{
		return 1;
	}

	unsigned int i = 0;

	for (i = iCurrentMileage + 1; i <= 999999; i++)
	{
		if (isDuiChenNum(i))
		{
			*piCarSpeed = (i - iCurrentMileage) / 2;
			return 0;
		}
	}

	return 1;
}

/*判断这个数是不是对称数*/
bool isDuiChenNum(const int num)
{
	int begin = 0, end = 0;
	char str[10] = { 0 };

	sprintf_s(str, "%d", num);
	end = strlen(str) - 1;

	while (begin