标签：atoi
Implement atoi to convert a string to an integer.
Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases.
Notes: It is intended for this problem to be specified vaguely (ie, no given input specs). You are responsible to gather all the input requirements up front.
字符串的操作，写程序经常性遇到，string这个类真的非常有用哟，题目要求自行实现atoi的功能：
class Solution
{
public:
int atoi(const char *str)
{
while(' ' == *str)
{
str++;
}
bool isNegative = false;
if('-' == *str)
{
isNegative = true;
str++;
}
else if('+' == *str)
{
str++;
}
long long ret = 0;
while(*str)
{
if( isdigit(*str) )
{
ret = ret * 10 + (*str - '0');
if(isNegative && (-ret <= INT_MIN))
{
return INT_MIN;
}
if(!isNegative && (ret >= INT_MAX))
{
return INT_MAX;
}
}
else
{
break;
}
str++;
}
return (isNegative ? -ret : ret);
}
};
【Leet Code】String to Integer (atoi) ——常考类型题
标签：atoi
原文地址：http://blog.csdn.net/u012771236/article/details/38859829
