程序员面试100题(算法)之把字符串转换成整数

此程序还没有判读sum是否溢出，待续。。

// 程序员面试100题(算法)之把字符串转换成整数#include "stdafx.h"#include <iostream>using namespace std;int state = 0;int ConvertStr(char *str){	int num = 0;	long sum = 0;	if(NULL == str)	{		cout << "input is empty" << endl;		state = 1;	}	else	{		char symbol = *str;		if(symbol == '+' || symbol == '-')		{			str++;		}		while(*str != '\0')		{			if(*str >= '0' && *str <= '9')			{				num = *str - '0';				sum = sum * 10 + num;				str++;			}			else			{				state = 1;				break;			}		}		if(symbol == '-')		{			sum = 0 - sum;		}	}	return sum;}int _tmain(int argc, _TCHAR* argv[]){	char *str = "-5462458";	long number = ConvertStr(str);	if(1 == state)		cout << "Wrong input" <<endl;	else		cout << number << endl;	return 0;}