[C++知识库]C++实现aoti()函数

#include<iostream>
using namespace std;
int my_aoti(const char*str)
{
	int flag = 1;
	int num = 0;

	//判断指针是否为空
	if (str == NULL)
	{
		cout << "ERROR" << endl;
		return 0 ;
	}

	//判断前面的符号
	if (*str == '-' || *str == '+')
	{
		if (*str == '-')
		{
			flag = -1;
			++str;
		}
		else
		{
			flag = 1;
			++str;
		}
	}

	while (*str != '\0')//判断字符串是否结束
	{
		if (*str >= '0'&&*str <= '9')
		{
			num = num * 10 + *str - '0';
			++str;
		}
		else
		{
			break;
		}
	}
	return num * flag;
}
int main()
{
	const char*ch1 = "33460";
	const char*ch2 = "-12345";
	const char*ch3 = "123.12";
	const char*ch4 = "+33460a";
	cout << my_aoti(ch1) << endl;
	cout << my_aoti(ch2) << endl;
	cout << my_aoti(ch3) << endl;
	cout << my_aoti(ch4) << endl;
}