C++练习打印一封信

 1 #include <iostream>
 2 #include <string>
 3 #include <sstream>
 4 
 5 using namespace std;
 6 
 7 void keep_window() { char ch; cin >> ch; }
 8 
 9 
10 int main()
11 {
12     string letter = "";
13     string first_name;
14     cout << "Enter your name :";
15     cin >> first_name;
16     string who_name; 
17     cout << "Enter the name of the person you want to write to:";
18     cin >> who_name;
19     
20     letter += "Dear " + who_name + ":\n";
21     letter += "    How are you? I am fine. I miss you. ";
22     letter += "I'd like to write a poem for you. ";
23     string friend_name; 
24     cout << "Enter the friend name: ";
25     cin >> friend_name;
26     
27     letter += "Have you seen " + friend_name + " lately? ";
28     char sex;
29     cout << "Enter sex for you friend:";
30     cin >> sex;
31     if (sex == 'm')
32         letter += "If you seen "  + friend_name + " please ask him to call me. ";
33     else
34         letter += "If you seen "  + friend_name + " please ask her to call me. ";
35     
36     int age;
37     cout << "Enter the age :";
38     cin >> age;
39     if (age <= 0 || age >= 110)
40         cout << "you're kidding!\n";
41     else
42     {
43         
44         ostringstream ostr ;
45         ostr << age;
46         letter += "I hear you just had a birthday and you are "+ ostr.str() + " years old. ";
47     }
48         
49     if (age < 12)
50     {
51         ostringstream ostr;
52         ostr << age+1;
53         letter += "Next year you will be " + ostr.str() + " years. ";
54     }
55     
56     else if (age <= 17)
57         letter += "Next year you will be able to vote. ";
58     else if (age > 70)
59         letter += "I hope you are enjoying retirement. ";
60         
61     letter += "\n\n";
62     letter += "Yours sincerely\n\n";
63     letter += first_name;
64     
65     cout << letter;
66     
67     keep_window();
68 }