IC210: String theory

Part 1: Lab prep

Make a lab07 directory.
Download the file part1.cpp and save it in the lab07 directory.
Compile like this
```
g++ -g part1.cpp -o part1
```
... and run once from the command-line. If you do an ls command, you'll see a bunch of new files have been created. These will be useful in the last part of the lab.

Part 2: define printSpaced

Create a program (call it lab07.cpp) with main

int main()
{
  cout << "["; printSpaced("wash"); cout << "]" << endl;
  cout << "["; printSpaced("HelloWorld!"); cout << "]" << endl;
  cout << "["; printSpaced("I am"); cout << "]" << endl;
  return 0;
}

... which means you'll have to define the printSpaced function. Hint: the prototype should be void printSpaced(string);. The output should be exactly:

[w a s h]
[H e l l o W o r l d !]
[I   a m]

In other words, printSpaced prints a string with a space inserted in between consecutive characters. Thus, "wash" gets printed as if it were "w a s h".

Submit as: ~/bin/submit -c=IC210 -p=Lab07 lab07.cpp

Part 3: define mkShadowString

Add the following code to lab07.cpp's main

string s1 = "food";
string s2 = mkShadowString(s1);
cout << "original: " << s1 << endl;
cout << "  shadow: " << s2 << endl;
string s3 = "require";
string s4 = mkShadowString(s3);
cout << "original: " << s3 << endl;
cout << "  shadow: " << s4 << endl;

... and define a function mkShadowString so that the program produces the output below:

original: food
  shadow: ____
original: require
  shadow: _______

In other words, mkShadowString takes a string as input, and returns a string of the same length, but consisting solely of underscores (_'s). Note: add this on to the previous part. That means keep the functions you already have.

Submit as: ~/bin/submit -c=IC210 -p=Lab07 lab07.cpp

Part 4: define crossOut

Often you want a function to modify an existing string, rather than return a new string. I want you to define a function crossOut that works this way. Add the following code to lab07.cpp's main:

string t1 = "Go get good food!";
cout << t1 << endl;
crossOut('o',t1);
cout << t1 << endl;
crossOut('g',t1);
cout << t1 << endl;

... and define a function crossOut so that the program produces the output below:

Go get good food!
G* get g**d f**d!
G* *et ***d f**d!

Since we want to modify the string that's passed to crossOut, we need to pass it by reference. Therefore, you'll want to use this prototype:

void crossOut(char c, string &s);

Submit as: ~/bin/submit -c=IC210 -p=Lab07 lab07.cpp

Part 5: define uncover

Add the following code to lab07.cpp's main:

string u1 = "housepet";
string u2 = "________";
cout << u2 << endl << endl;
bool t;
t = uncover(u1,u2,'e');
cout << u1 << endl;
cout << u2 << " there " << (t ? "were " : "were not ") << "e's!"  << endl;
cout << endl;
t = uncover(u1,u2,'q');
cout << u1 << endl;
cout << u2 << " there " << (t ? "were " : "were not ") << "q's!"  << endl;

... and define a function uncover so that the program produces the output below.

________

housepet
____e_e_ there were e's!

housepet
____e_e_ there were not q's!

In other words, all occurrences of the given character within the first string, are copied into the second string at the positions at which they were found. True is returned if occurrences were found, false is returned otherwise. You may assume the string arguments have the same length.

Submit as: ~/bin/submit -c=IC210 -p=Lab07 lab07.cpp

Part 6: define fixFirstDisagreement

Add the following code to lab07.cpp's main:

string w1 = "id card!";
string w2 = "it bard!";
do {
  cout << w2 << endl;
} while(fixFirstDisagreement(w1,w2));

... and define a function fixFirstDisagreement so that the program produces the output below.

it bard!
id bard!
id card!

In other words, fixFirstDisagreement looks for the first (from left to right) position at which the two strings disagree, and modifies the second string to match the first string at that position. It returns true if the second string has been modified, and false if no changes were made to the second string.

Submit as: ~/bin/submit -c=IC210 -p=Lab07 lab07.cpp

Part 7: Going further, Hangman

Add the following code to your main, compile and run.

  {
    string fh = "  ____\n  |   |\n _O_  |\n  |   |\n / \\  |\n______|_\n";
    string ch = "  ____\n  |   |\n      |\n      |\n      |\n______|_\n";
    do {
      cout << ch << endl;
      cout << "press <enter>" << endl;
    } while(cin.get() == '\n' && fixFirstDisagreement(fh, ch));
  }

If you ran this program, this should put you very much in mind of a game ... hangman! As a challange to you, use the functions you implemented in the earlier parts of this lab to implement the hangman game (call the file hangman.cpp). A few notes for you:

if you want to see an implementation of this game in action, try this:
```
pushd ~wcbrown/bin; ./hangman; popd
```
if you ran the program from Part 1, you'll find a whole slew of files got created as a result. They're word lists. I recommend that you use words09.txt, which contains 909 common 9-letter words, one per line. You can generate a random number from 1-909, and use that to choose a random word from the file words09.txt. That way, each time you play the game you get a different word.
I like a "command" style for games like this. I.e. the user types commands at each step. I chose "letter <char>", "solve <string>" and "quit" as my three commands.
remember: get a small part of the functionality working, then compile-test-debug. Get a litte more of the functionality working, then compile-test-debug. Keep doing this until you're finished.

Note: If you get a nice working game, please demo it to your instructor.

Submit as: ~/bin/submit -c=IC210 -p=Lab07 lab07.cpp hangman.cpp