add solution of hw1

hws/spotify_playlists/README.txt

@@ -10,14 +10,14 @@ List the names of everyone you talked to about this assignment
 LMS, etc.), and all of the resources (books, online reference
 material, etc.) you consulted in completing this assignment.
 
-< insert collaborators / resources >
+Qijun Lu, Google, Stack Overflow, W3School
 
 Remember: Your implementation for this assignment must be done on your
 own, as described in "Academic Integrity for Homework" handout.
 
 
 
-ESTIMATE OF # OF HOURS SPENT ON THIS ASSIGNMENT:  2 hr
+ESTIMATE OF # OF HOURS SPENT ON THIS ASSIGNMENT:  16 hr
 
 
 
@@ -27,6 +27,7 @@ ESTIMATE OF # OF HOURS SPENT ON THIS ASSIGNMENT:  2 hr
 MISC. COMMENTS TO GRADER:  
 Optional, please be concise!
 
+Ignore the debug codes. To enable it, take `debug` as the fourth argument.
 
 ## Reflection and Self Assessment
 
@@ -38,4 +39,8 @@ What parts of the assignment did you find challenging? Is there anything that
 finally "clicked" for you in the process of working on this assignment? How well
 did the development and testing process go for you?
 
-< insert reflection >
+During this homework, I used the experience from CS1, which create debugging
+output frequently. The hardest part is handle strings. Merge, split, remove,
+add. I referenced many examples from internet. The language server in VSCode
+also help, it shows a short tip about why it's an error. Anyhow, I believe I
+can do better next time.

hws/spotify_playlists/nyplaylists.cpp

@@ -1,9 +1,246 @@
-//import some basic library
+//An implement of CSCI-1200 HW1 Spotify Playlists
+//Author: Jinshan ZHou
+//Date: 2025/1/16
+#include <vector>
+#include <string>
 #include <iostream>
-#include <cmath>
-#include <cstdlib>
+#include <fstream>
+//#include <algorithm>
+//#include <sstream>
+//#include <cmath>
+//#include <cstdlib>
 
-int main() {
-    std::cout << "Hello, World!" << std::endl;
+std::string get_text(const std::string &fname) {
+    //load a text file into a string
+    std::ifstream inFile(fname);
+    //check if file exists
+    if (!inFile) {
+        std::cout << "Error: File not found" << std::endl;
+        return "";
+    }
+    std::string text;
+    std::string line;
+    while (std::getline(inFile, line)) {
+        text += line;
+        text += "\n";
+    }
+    inFile.close();
+
+    return text;
+}
+
+std::vector<std::string> load_list(const std::string &fname) {
+    //load a text file into a vector of strings
+    std::string text = get_text(fname);
+
+    std::vector<std::string> lines;
+    std::size_t start = 0;
+    std::size_t end   = 0;
+    while ((end = text.find('\n', start)) != std::string::npos) {
+        lines.push_back(text.substr(start, end - start));
+        start = end + 1;    
+    }
+    if (start < text.size()) {
+        lines.push_back(text.substr(start));
+    }
+
+    return lines;
+}
+
+void debug_print(const std::string &msg) {
+    std::cout << "DEBUG: " << msg << std::endl;
+}
+
+bool is_all_digits(const std::string& s) {
+    //check if string is int
+    for (char c : s) {
+        if (!std::isdigit(static_cast<unsigned char>(c))) {
+            return false;
+        }
+    }
+    return !s.empty();
+}
+
+std::vector<std::string> tokenizer(const std::string &s) {
+    //split string into tokens
+    std::vector<std::string> tokens;
+    std::string token;
+    for (char c : s) {
+        if (c == ' ') {
+            tokens.push_back(token);
+            token = "";
+        } else {
+            token += c;
+        }
+    }
+    tokens.push_back(token);
+    return tokens;
+}
+
+bool check_in_list (const std::string &s, const std::vector<std::string> &list) {
+    //check if string is in list
+    for (std::string item : list) {
+        if (s == item) {
+            return true;
+        }
+    }
+    return false;
+}
+
+void remove_in_list (const std::string &s, std::vector<std::string> &list) {
+    //remove string from list
+    if (!check_in_list(s, list)) {return;}
+    for (int i = 0; i < list.size(); i++) {
+        if (list[i] == s) {
+            list.erase(list.begin() + i);
+            return;
+        }
+    }
+}
+
+int get_current (std::vector<std::string> &playlist) {
+    //return the index of the string has word current at the end
+    for (int i = 0; i < playlist.size(); i++) {
+        if (playlist[i].find("current") != std::string::npos) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+std::string build_song (const std::vector<std::string> &tokens, const int &start, const int &end) {
+    //build string from tokens w/ start and end positions
+    std::string song;
+    for (int i = start; i < end; i++) {
+        song += tokens[i];
+        if (i != end - 1) {
+            song += " ";
+        }
+    }
+    return song;
+}
+
+void write_list(const std::string &fname, const std::vector<std::string> &list) {
+    //write list to file
+    std::ofstream outFile(fname);
+    for (std::string line : list) {
+        outFile << line << std::endl;
+    }
+    outFile.close();
+}
+
+int main(int argc, char *argv[]) {
+    //take 3 arguments
+    if (argc < 3) {
+        std::cout << "Error: Not enough arguments" << std::endl;
+        return 1;
+    }
+    //load arguments
+    std::string playlist_fname = argv[1];
+    std::string action_list_fname = argv[2];
+    std::string output_fname = argv[3];
+    //turn on debug mode is last argument is debug
+    bool debug_mode = false;
+    if (std::string(argv[argc - 1]) == "debug") {
+        debug_mode = true;
+    }
+
+    if (debug_mode) {
+        debug_print("playlist_fname =" + playlist_fname);
+        debug_print("action_list_fname =" + action_list_fname);
+        debug_print("output_fname =" + output_fname);
+    }
+    //load working files
+    std::vector<std::string> playlist = load_list(playlist_fname);
+    std::vector<std::string> action_list = load_list(action_list_fname);
+    //get current playing song id
+    int current_song_id = get_current(playlist);
+    if (debug_mode) {
+        debug_print("current_song_id = " + std::to_string(current_song_id));
+    }
+    //execute actions
+    for (std::string command : action_list) {
+        if (debug_mode) {
+            debug_print("Command = " + command);
+        }
+        //split command into tokens
+        std::vector<std::string> tokens = tokenizer(command);
+        if (tokens[0] == "next") {
+            current_song_id = get_current(playlist);
+            //remove "current" tag
+            playlist[current_song_id].erase(playlist[current_song_id].length() - 8);
+            if (current_song_id == playlist.size() - 1) {
+                current_song_id = 0;
+            } else {
+                current_song_id++;
+            }
+            //update current song
+            playlist[current_song_id] += " current";
+        }
+        if (tokens[0] == "previous") {
+            current_song_id = get_current(playlist);
+            //remove "current" tag
+            playlist[current_song_id].erase(playlist[current_song_id].length() - 8);
+            if (current_song_id == 0) {
+                current_song_id = playlist.size() - 1;
+            } else {
+                current_song_id--;
+            }
+            //update current song
+            playlist[current_song_id] += " current";
+        }
+        if (tokens[0] == "add") {
+            std::string song;
+            song = build_song(tokens, 1, tokens.size());
+            playlist.push_back(song);
+            
+            if (debug_mode) {
+                debug_print("Added = " + song);
+            }
+        }
+        if (tokens[0] == "remove") {
+            std::string song;
+            song = build_song(tokens, 1, tokens.size());
+            remove_in_list(song, playlist);
+
+            if (debug_mode) {
+                debug_print("Removed = " + song);
+            }
+        }
+        if (tokens[0] == "move") {
+            if (is_all_digits(tokens.back())){
+                //set target position
+                int dest = std::stoi(tokens.back());
+                //build song from tokens
+                std::string song;
+                song = build_song(tokens, 1, tokens.size() - 1);
+                //fix song name if it has current tag
+                if (!check_in_list(song, playlist) &&
+                    !check_in_list(song + " current", playlist)) {continue;}
+                else if (check_in_list(song + " current", playlist)) {
+                    song += " current";
+                }
+                remove_in_list(song, playlist);
+                playlist.insert(playlist.begin() + dest - 1, song);
+
+                if (debug_mode) {
+                    debug_print("Moved " + song + " to " + std::to_string(dest));
+                }
+            } else {
+                std::cout << "ERROR: Missing move destination" << std::endl;
+                continue;
+            }
+        }
+        
+    }
+    //write back file
+    write_list(output_fname, playlist);
+
+    if (debug_mode) {
+        debug_print("Playlist Content:");
+        for (std::string line : playlist) {
+            std::cout << line << std::endl;
+        }
+    }
     return 0;
 }

hws/spotify_playlists/output.txt

@@ -0,0 +1,18 @@
+"Someone Like You" Adele
+"Shallow" Lady Gaga, Bradley Cooper
+"Happier" Marshmello
+"Blinding Lights" The Weeknd
+"Levitating" Dua Lipa
+"Uptown Funk" Mark Ronson, Bruno Mars
+"Imagine" John Lennon
+"Bad Romance" Lady Gaga current
+"Hotel California" Eagles
+"Bohemian Rhapsody" Queen
+"Stairway to Heaven" Led Zeppelin
+"Smells Like Teen Spirit" Nirvana
+"Like a Rolling Stone" Bob Dylan
+"Hey Jude" The Beatles
+"Perfect" Ed Sheeran
+"Rolling in the Deep" Adele
+"Bad Guy" Billie Eilish
+"Dance Monkey" Tones and I