类型转换问题（持续更新）

1.atoi(字符串转整数)

需要考虑的问题：1.空格；2.符号3.溢出

#include <iostream>using namespace std;#include <string>int my_atoi(string s){int flag = 1;int num = 0;for (int i = s.find_first_not_of(' '); i < s.size();){if (s[i] == '-' || s[i] == '+'){if (s[i] == '-')flag = -1;i++;}while (s[i] >= '0' && s[i] <= '9'){num = num * 10 + (s[i] - '0');i++;if (num * flag >= 2147483647)return 2147483647;if (num * flag <= -2147483647)return -2147483647;}return num * flag;}}