numeric_limts

用于取得某数据类型的特征：numeric_limits<T>

#include <iostream> #include <limits> #include <string>   using namespace std;   int main() {        cout << boolalpha;          //看函数名字就知道了。        cout << "max(short):" << std::numeric_limits<short>::max() <<endl;        cout << "max(int):" << numeric_limits<int>::max() <<endl;        cout << "max(long):" << numeric_limits<long>::max() <<endl;          cout << "min(float):" << numeric_limits<float>::min() <<endl;        cout << "max(double):" << numeric_limits<double>::max() <<endl;        cout << "max(long double):" << numeric_limits<long double>::max() <<endl;          cout << "is_signed(char):" << numeric_limits<char>::is_signed << endl;        cout << "is_specialized(string)" << numeric_limits<string>::is_specialized << endl;          return 0; }