From 剑指Offer 何海涛 著

#include 
     
      #include 
      
        #include 
       
        bool g_valid = false;int StrToInt(const std::string& s) {    long long res = 0ll;    int n = s.size();    int i= 0;    g_valid = true;    while(i
        
          (long)0x7fffffff || isNegative&& -res < (long)0x80000000) {            g_valid = false;            return 0;        }    }    if(i< n) {        g_valid = false;        return 0;    }        return isNegative ? -res : res;}
        
       
      
     

测试集:

void test(const std::string &s, int n, bool valid) {    std::cout << std::boolalpha<< (StrToInt(s) == n && valid == g_valid) << std::endl;}int main(int argc, char* argv[]) {    test("", 0, false);    test("  ", 0, false);        test("+", 0, false);    test("-", 0, false);    test("123", 123, true);    test("+0", 0, true);    test("-0", 0, true);    test("+123", 123, true);    test("-123", -123, true);        test("abc", 0, false);    test("1a33", 0, false);        //有效的最大正整数, 0x7FFFFFFF    test("+2147483647", 2147483647, true);    test("+2147483648", 0, false);        //有效的最小负整数, 0x80000000    test("-2147483648", -2147483648, true);    test("-2147483649", 0, false);    return 0;}