progvaltest.cpp

C++编程思想第二版第一册答案

//: C20:ProgValTest.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
//{L} ProgVals
#include "ProgVals.h"
using namespace std;

string defaults[][2] = {
  { "color", "red" },
  { "size", "medium" },
  { "shape", "rectangular" },
  { "action", "hopping"},
};

const char* usage = "usage:\n"
"ProgValTest [flag1=val1 flag2=val2 ...]\n"
"(Note no space around '=')\n"
"Where the flags can be any of: \n"
"color, size, shape, action \n";

// So it can be used globally:
ProgVals pvals(defaults, 
  sizeof defaults / sizeof *defaults);

class Animal {
  string color, size, shape, action;
public:
  Animal(string col, string sz, 
    string shp, string act) 
    :color(col),size(sz),shape(shp),action(act){}
  // Default constructor uses program default
  // values, possibly change on command line:
  Animal() : color(pvals["color"]), 
    size(pvals["size"]), shape(pvals["shape"]),
    action(pvals["action"]) {}
  void print() {
    cout << "color = " << color << endl
      << "size = " << size << endl
      << "shape = " << shape << endl
      << "action = " << action << endl;
  }
  // And of course pvals can be used anywhere
  // else you'd like.
};

int main(int argc, char* argv[]) {
  // Initialize and parse command line values
  // before any code that uses pvals is called:
  pvals.parse(argc, argv, usage);
  pvals.print();
  Animal a;
  cout << "Animal a values:" << endl;
  a.print();
} ///:~