Header File:

#ifndef BROWSERHISTORY_H #define BROWSERHISTORY_H

#include #include "stack.h"

using namespace std;

class BrowserHistory { public: // Creates a new browser history with only one page visited: default_url BrowserHistory(string default_url);

// Returns the current page. string current_url();

// Moves the browser to a new page url via, // e.g., clicking a link, typing into the address bar, etc. void go_to_url(string url);

// Moves back (into the past) by one url. // // If there is no past url to move to, does nothing. void back();

// Returns whether there is a url in the past, // i.e. whether the back button can be pushed. bool can_go_back();

// Returns how many urls are in the past, // i.e. how many times in a row the back button could be pushed. int past_url_count();

// Moves forward (into the future) by one url. // // If there is no future url to move to, does nothing. void forward();

// Returns whether there is a url in future, // i.e. whether the future button can be pushed. bool can_go_forward();

// Returns how many urls are in the future, // i.e. how many times in a row the forward button could be pushed. int future_url_count();

private: // Two stacks of strings - these are the only variables you need! // See http://www.cplusplus.com/reference/stack/stack/ for class reference. Stack past; Stack future; };

#endif

Main File:

#include #include "browserhistory.h"

inline void _test(const char* expression, const char* file, int line) { cerr << "test(" << expression << ") failed in file " << file << ", line " << line << "." << endl; abort(); }

#define test(EXPRESSION) ((EXPRESSION) ? (void)0 : _test(#EXPRESSION, __FILE__, __LINE__))

void interactive_mode() { BrowserHistory bh("http://google.com"); cout << "Starting at " << bh.current_url() << "." << endl; cout << "Choose (B)ack, (F)orward, or enter a url to go to." << endl;

string line; while (cin) { string line; getline(cin, line); if (line == "B") { if (bh.can_go_back()) { bh.back(); cout << " Now at " << bh.current_url() << endl; } else cout << " Cannot go back." << endl;

} else if (line == "F") { if (bh.can_go_forward()) { bh.forward(); cout << " Now at " << bh.current_url() << endl; } else cout << " Cannot go forward." << endl; } else if (line.size() > 0) { bh.go_to_url(line); cout << " Now at " << bh.current_url() << endl; } } exit(0); }

int main() { // Uncomment line below to use your BrowserHistory interactively. // // interactive_mode();

// Comments below indicate the current (expected) state of the history. // Example: [url1, url2, url3, (url4), url5, url6] // The urls are listed oldest to newest from left to right, // and the url in parentheses is the current url.

// History: [(google.com)] BrowserHistory bh("http://google.com"); test(bh.current_url() == "http://google.com"); test(!bh.can_go_back()); test(!bh.can_go_forward()); test(bh.past_url_count() == 0); test(bh.future_url_count() == 0);

bh.go_to_url("http://netflix.com"); bh.go_to_url("http://amazon.com"); bh.go_to_url("http://utrgv.edu"); // History: [google.com, netflix.com, amazon.com, (utrgv.edu)] test(bh.current_url() == "http://utrgv.edu"); test(bh.can_go_back()); test(!bh.can_go_forward()); test(bh.past_url_count() == 3); test(bh.future_url_count() == 0);

bh.back(); bh.back(); // History: [google.com, (netflix.com), amazon.com, utrgv.edu] test(bh.current_url() == "http://netflix.com"); test(bh.can_go_back()); test(bh.can_go_forward()); test(bh.past_url_count() == 1); test(bh.future_url_count() == 2);

bh.forward(); // History: [google.com, netflix.com, (amazon.com), utrgv.edu] test(bh.current_url() == "http://amazon.com"); test(bh.can_go_back()); test(bh.can_go_forward()); test(bh.past_url_count() == 2); test(bh.future_url_count() == 1);

// History: [google.com, netflix.com, amazon.com, (youtube.com)] bh.go_to_url("http://youtube.com"); test(bh.current_url() == "http://youtube.com"); test(bh.can_go_back()); test(!bh.can_go_forward()); test(bh.past_url_count() == 3); test(bh.future_url_count() == 0); bh.forward(); // Can't go forward any more, so do nothing test(bh.current_url() == "http://youtube.com");

bh.back(); bh.back(); bh.back(); // History: [(google.com), netflix.com, amazon.com, youtube.com] test(bh.current_url() == "http://google.com"); bh.back(); // Can't go back any more, so do nothing test(bh.current_url() == "http://google.com");

// Larger test string url("http://url00.com"); for (int i = 0; i < 100; ++i) { url[10] = i / 10 + '0'; url[11] = i % 10 + '0'; bh.go_to_url(url); } // History: [url00.com, url01.com, url02.com, ..., (url99.com)] for (int i = 0; i < 49; ++i) bh.back(); // History: [url00.com, url01.com, ..., (url50.com), ..., url99.com] test(bh.current_url() == "http://url50.com");

cout << "Assignment complete." << endl; system("pause"); }

stack:

#include "stack.h" #include using namespace std;

Stack::Stack() { count = 0; }; void Stack::push(string item) { data[count] = item; count++; }; void Stack::pop() { if (count > 0) { count--; } else { data[count] = ""; }

}; string Stack::top() { if (count > 0) { return data[count - 1]; } else { return ""; }

}; int Stack::size() {

return count;

};

Implement the body of the header functions to display "assignment complete" with no errors or warnings!!