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Const value const pointer question

Aug 25, 2023LeifMessinger
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PlaylistNode.cpp (lab 9)

Nov 18, 2022AustinLeath

0 likes • 0 views

#include <string>
#include <iostream>
#include "PlaylistNode.h"
using namespace std;
PlaylistNode::PlaylistNode() {
uniqueID = "none";
songName = "none";
artistName = "none";
songLength = 0;
nextNodePtr = 0;
}
PlaylistNode::PlaylistNode(string uniqueID_, string songName_, string artistName_, int songLength_) {
uniqueID = uniqueID_;
songName = songName_;
artistName = artistName_;
songLength = songLength_;
nextNodePtr = 0;
}
void PlaylistNode::InsertAfter(PlaylistNode* ptr) {
this->SetNext(ptr->GetNext());
ptr->SetNext(this);
}
void PlaylistNode::SetNext(PlaylistNode* ptr) {
nextNodePtr = ptr;
}
string PlaylistNode::GetID() {
return uniqueID;
}
string PlaylistNode::GetSongName() {
return songName;
}
string PlaylistNode::GetArtistName() {
return artistName;
}
int PlaylistNode::GetSongLength() {
return songLength;
}
PlaylistNode* PlaylistNode::GetNext() {
return nextNodePtr;
}
void PlaylistNode::PrintPlaylistNode() {
cout << "Unique ID: " << uniqueID << endl;
cout << "Song Name: " << songName << endl;
cout << "Artist Name: " << artistName << endl;
cout << "Song Length (in seconds): " << songLength << endl;
}
Playlist::Playlist() {
head = tail = 0;
}
void Playlist::AddSong(string id, string songname, string artistname, int length) {
PlaylistNode* n = new PlaylistNode(id, songname, artistname, length);
if (head == 0) {
head = tail = n;
}
else {
n->InsertAfter(tail);
tail = n;
}
}
bool Playlist::RemoveSong(string id) {
if (head == NULL) {
cout << "Playlist is empty" << endl;
return false;
}
PlaylistNode* curr = head;
PlaylistNode* prev = NULL;
while (curr != NULL) {
if (curr->GetID() == id) {
break;
}
prev = curr;
curr = curr->GetNext();
}
if (curr == NULL) {
cout << "\"" << curr->GetSongName() << "\" is not found" << endl;
return false;
}
else {
if (prev != NULL) {
prev ->SetNext(curr->GetNext());
}
else {
head = curr->GetNext();
}
if (tail == curr) {
tail = prev;
}
cout << "\"" << curr->GetSongName() << "\" removed." << endl;
delete curr;
return true;
}
}
bool Playlist::ChangePosition(int oldPos, int newPos) {
if (head == NULL) {
cout << "Playlist is empty" << endl;
return false;
}
PlaylistNode* prev = NULL;
PlaylistNode* curr = head;
int pos;
if (head == NULL || head == tail) {
return false;
}
for (pos = 1; curr != NULL && pos < oldPos; pos++) {
prev = curr;
curr = curr->GetNext();
}
if (curr != NULL) {
string currentSong = curr->GetSongName();
if (prev == NULL) {
head = curr->GetNext();
}
else {
prev->SetNext(curr->GetNext());
}
if (curr == tail) {
tail = prev;
}
PlaylistNode* curr1 = curr;
prev = NULL;
curr = head;
for (pos = 1; curr != NULL && pos < newPos; pos++) {
prev = curr;
curr = curr->GetNext();
}
if (prev == NULL) {
curr1->SetNext(head);
head = curr1;
}
else {
curr1->InsertAfter(prev);
}
if (curr == NULL) {
tail = curr1;
}
cout << "\"" << currentSong << "\" moved to position " << newPos << endl;
return true;
}
else {
cout << "Song's current position is invalid" << endl;
return false;
}
}
void Playlist::SongsByArtist(string artist) {
if (head == NULL) {
cout << "Playlist is empty" << endl;
}
else {
PlaylistNode* curr = head;
int i = 1;
while (curr != NULL) {
if (curr->GetArtistName() == artist) {
cout << endl << i << "." << endl;
curr->PrintPlaylistNode();
}
curr = curr->GetNext();
i++;
}
}
}
int Playlist::TotalTime() {
int total = 0;
PlaylistNode* curr = head;
while (curr != NULL) {
total += curr->GetSongLength();
curr = curr->GetNext();
}
return total;
}
void Playlist::PrintList() {
if (head == NULL) {
cout << "Playlist is empty" << endl;
}
else {
PlaylistNode* curr = head;
int i = 1;
while (curr != NULL) {
cout << endl << i++ << "." << endl;
curr->PrintPlaylistNode();
curr = curr->GetNext();
}
}
}

Daily: Cutting a Wall

Dec 20, 2021aedrarian

0 likes • 0 views

/*
Good morning! Here's your coding interview problem for today.
This problem was asked by LinkedIn.
A wall consists of several rows of bricks of various integer lengths and uniform height. Your goal is to find a vertical line going from the top to the bottom of the wall that cuts through the fewest number of bricks. If the line goes through the edge between two bricks, this does not count as a cut.
For example, suppose the input is as follows, where values in each row represent the lengths of bricks in that row:
[[3, 5, 1, 1],
[2, 3, 3, 2],
[5, 5],
[4, 4, 2],
[1, 3, 3, 3],
[1, 1, 6, 1, 1]]
The best we can we do here is to draw a line after the eighth brick, which will only require cutting through the bricks in the third and fifth row.
Given an input consisting of brick lengths for each row such as the one above, return the fewest number of bricks that must be cut to create a vertical line.
AUTHORS NOTE:
Makes following assumptions:
- Each row is same length
- Data is in file called "data.dat" and formatted in space-separated rows
- The cuts at the beginning and end of the wall are not solutions
This requires the following file named data.dat that is a space separated file, or similar formatted file:
----START FILE----
3 5 1 1
2 3 3 2
5 5
4 4 2
1 3 3 3
1 1 6 1 1
----END FILE----
*/
#include <algorithm>
#include <iostream>
#include <fstream>
#include <map>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
int main()
{
vector<vector<int>> wall;
ifstream in;
in.open("data.dat");
if(!in.good())
{
cout << "ERROR: File failed to open properly.\n";
}
/* Get input from space separated file */
string line;
while(!in.eof())
{
getline(in, line);
int i;
vector<int> currv;
stringstream strs(line);
while(strs >> i)
currv.push_back(i);
wall.push_back(currv);
}
/* Convert each value from "length of brick" to "position at end of brick" */
for(int y = 0; y < wall.size(); y++)
{
wall.at(y).pop_back(); //Delet last val
for(int x = 1; x < wall.at(y).size(); x++) //Skip the first bc data doesn't need change
wall.at(y).at(x) += wall.at(y).at(x-1);
}
/* Check output. COMMENT OUT */
// for(auto row : wall)
// {
// for(int pos : row)
// cout << pos << " ";
// cout << endl;
// }
/* Determine which ending position is most common, and cut there */
//Exclude final position, which will be the size of the wall
int mode = -1;
int amt = -1;
vector<int> tried;
for(auto row : wall)
{
for(int pos : row) //For each pos in the wall
{
//Guard. If pos is contained in the list, skip pos
if(find(tried.begin(), tried.end(), pos) != tried.end())
continue;
tried.push_back(pos);
/* Cycle through each row to see if it contains the pos */
int curramt = 0;
for(auto currrow : wall)
{
if( find( currrow.begin(), currrow.end(), pos ) != currrow.end() )
curramt++;
}
//cout << pos << " " << curramt << endl;
if(curramt > amt)
{
amt = curramt;
mode = pos;
}
}
}
cout << "Please cut at position " << mode << endl;
cout << "This will cut through " << (wall.size() - amt) << " bricks." << endl;
return 0;
}

wordScore.cpp

Apr 16, 2023LeifMessinger

0 likes • 0 views

#include <iostream>
#include <string> //Should already be in iostream
#include <cstdlib>
//A word score adds up the character values. a-z gets mapped to 1-26 for the values of the characters.
//wordScore [wordValue]
//Pipe in the input into stdin, or type the words yourself.
//Lowercase words only
int characterValue(const char b){
return ((b >= 'a') && (b <= 'z'))? ((b - 'a') + 1) : 0;
}
int main(int argc, char** argv){
//The first argument specifies if you are trying to look for a certain word score
int wordValue = (argc > 1)? std::atoi(argv[1]) : 0;
std::string line;
while(std::getline(std::cin, line)){
int sum = 0;
for(const char c : line){
sum += characterValue(c);
}
if(wordValue){ //If wordValue is 0 or the sum is the correct value
if(wordValue == sum){
std::cout << line << std::endl;
}
} else {
std::cout << sum << "\t" << line << std::endl;
}
}
return 0;
}

Big O(n^2) Ascending Sort

Nov 18, 2022AustinLeath

1 like • 7 views

#include <iostream>
using namespace std;
int main() {
int arr[5];
for(int i = 0; i < 5; i++) {
arr[i] = i;
}
for(int i = 0; i < 5; i++) {
cout << "Outputting array info at position " << i + 1 << ": " << arr[i] << endl;
}
for(int i=0;i<5;i++)
{
for(int j=i+1;j<5;j++)
{
if(arr[i]>arr[j])
{
int temp=arr[i];
arr[i]=arr[j];
arr[j]=temp;
}
}
}
cout << endl;
for(int i = 0; i < 5; i++) {
cout << "Outputting sorted array info at position " << i + 1 << ": " << arr[i] << endl;
}
return 0;
}

C++ Scanner

Jul 16, 2024LeifMessinger

0 likes • 10 views

//===============Header File==================
#include <iostream>
#include <sstream> //stringbuf
#include <utility> //exchange
//Couple rules:
//Characters given through the getter functions have to be removed from the buffer.
//This is so that bufferEmpty() == buffer.in_avail() > 0 basically always.
//skipWhitespace doesn't remove the text from the buffer, but it does return the number of characters.
//nextWord will trim whitespace before the word
//nextInt will trim non-numbers before the number
//hasNextInt and hasNextWord will trim the whitespace. If you think you need it, you should get nextWhitespace before doing any of those.
//Whitespace after a word or an int is left on the buffer.
//nextWhitespace will (get and) remove whitespace until the end of the line, including the newline character, but stops before the next line.
//nextWhitespace won't read the next line when called before the end of the line, and it won't prompt the user for the next line if interactive.
//If nextWhitespace is called after reading the end of the line, then it will read a new line into the buffer, which will prompt the user.
//It acts like nextLine, but if there's something non-whitespace on the current line it stops there.
class Scanner {
public:
std::stringbuf buffer;
std::istream& input;
Scanner(std::istream& in = std::cin) : buffer(), input(in) {}
//Buffer debugging
bool fillBuffer();
bool bufferEmpty();
void printBufferEmpty();
std::string getBuffer();
size_t bufferLength();
void printBufferStats();
//Int
bool hasNextInt();
int nextInt();
//Word
bool hasNextWord();
std::string nextWord();
//Line
bool hasNextLine();
//Whitespace
size_t skipWhitespace(); //Prob should be private, but I don't believe in that private shit.
bool hasNextWhitespace();
std::string nextWhitespace();
std::string nextWhitespaceAll();
std::string nextLine();
};
//===============Source File==================
bool Scanner::fillBuffer() { //Returns if it had to get the next line from the input.
const bool badInput = input.eof() || input.bad();
const bool shouldFillBuffer = bufferEmpty() && !badInput;
if (shouldFillBuffer) {
std::string line;
if (std::getline(input, line)) {
buffer.str(buffer.str() + line + "\n");
}
}
return shouldFillBuffer;
}
bool Scanner::bufferEmpty(){
return buffer.str() == "";
}
void Scanner::printBufferEmpty(){
std::cout << "The buffer is " << (bufferEmpty()? "" : "not") << " empty." << std::endl;
}
std::string Scanner::getBuffer(){
return buffer.str();
}
size_t Scanner::bufferLength(){
return buffer.str().length();
}
void Scanner::printBufferStats(){
if(bufferEmpty()){
std::cout << "The buffer is \"\"" << std::endl;
return;
}
std::cout << "The length of the buffer is " << bufferLength() << std::endl;
if(buffer.sgetc() == '\r'){
std::cout << "The buffer is \\r\\n" << std::endl;
}else if(buffer.sgetc() == '\n'){
std::cout << "The buffer is \\n" << std::endl;
}
}
bool Scanner::hasNextInt() {
return hasNextWord() && (std::isdigit(buffer.sgetc()) || buffer.sgetc() == '-');
}
int Scanner::nextInt() {
if (!hasNextInt()) { //Will fill the buffer if not filled. Will also trim whitespace.
return 0;
}
std::string num;
size_t charactersRead = 0;
while (buffer.in_avail() > 0 && (std::isdigit(buffer.sgetc()) || buffer.sgetc() == '-')) {
num += buffer.sbumpc();
++charactersRead;
}
buffer.str(buffer.str().erase(0, charactersRead));
return std::stoi(num);
}
bool Scanner::hasNextWord() {
nextWhitespaceAll();
return buffer.in_avail() > 0;
}
std::string Scanner::nextWord() {
if (!hasNextWord()) { //Will fill the buffer if not filled. Will also trim whitespace.
return "";
}
std::string word;
size_t charactersRead = 0;
while (buffer.in_avail() > 0 && !std::isspace(buffer.sgetc())) {
word += buffer.sbumpc();
++charactersRead;
}
buffer.str(buffer.str().erase(0, charactersRead));
return word;
}
bool Scanner::hasNextLine() {
return (!bufferEmpty()) || fillBuffer();
}
size_t Scanner::skipWhitespace() { //Returns characters read
size_t charactersRead = 0;
while (buffer.in_avail() > 0 && std::isspace(buffer.sgetc())) {
buffer.sbumpc();
++charactersRead;
}
return charactersRead;
}
bool Scanner::hasNextWhitespace(){
fillBuffer();
return buffer.in_avail() > 0 && std::isspace(buffer.sgetc());
}
std::string Scanner::nextWhitespace() {
if (!hasNextWhitespace()) { //Will fill the buffer if not filled
return "";
}
const size_t charactersRead = skipWhitespace();
std::string whitespace = buffer.str().substr(charactersRead);
buffer.str(buffer.str().erase(0, charactersRead));
return whitespace;
}
std::string Scanner::nextWhitespaceAll(){
std::string whitespace;
while(hasNextWhitespace()){
std::string gottenWhiteSpace = nextWhitespace();
whitespace += gottenWhiteSpace;
}
return whitespace;
}
std::string Scanner::nextLine(){
if (!hasNextLine()) {
return "";
}
fillBuffer();
//Swap out the old buffer with an empty buffer, and get the old buffer as a variable.
std::string line = std::exchange(buffer, std::stringbuf()).str();
//Remove the newline.
if(line[line.length() - 1] == '\n' || line[line.length() - 1] == '\r' ) line.pop_back();
if(line[line.length() - 1] == '\r' || line[line.length() - 1] == '\n' ) line.pop_back();
return line;
}
//=================Word and Int test=================
while(bruh.hasNextInt() || bruh.hasNextWord()){
std::cout << "started loop" << std::endl;
if(bruh.hasNextInt()){
std::cout << "Int: " << bruh.nextInt() << " " << std::endl;
}else{
std::cout << "Word: " << bruh.nextWord() << " " << std::endl;
}
bruh.nextWhitespace();
}
//===================Line test======================
for(int count = 1; bruh.hasNextLine(); ++count){
std::string line = bruh.nextLine();
std::cout << "Line " << count << ": " << line << std::endl;
}

Daily: Find missing array value

Aug 5, 2023usama

1 like • 5 views

/*
Good morning! Here's your coding interview problem for today.
This problem was asked by Stripe.
Given an array of integers, find the first missing positive integer in linear time and constant space. In other words, find the lowest positive integer that does not exist in the array. The array can contain duplicates and negative numbers as well.
For example, the input [3, 4, -1, 1] should give 2. The input [1, 2, 0] should give 3.
You can modify the input array in-place.
*/
#include <iostream>
using namespace std;
int calcMissing(int* input, int size)
{
int sum = 0;
int n = 1; //add one to account for missing value
for(int i = 0; i < size; i++)
{
if(input[i] > 0)
{
sum += input[i];
n++;
}
}
//If no numbers higher than 0, answer is 1
if(sum == 0)
return 1;
return (n*(n+1)/2) - sum; //Formula is expectedSum - actualSum
/* expectedSum = n*(n+1)/2, the formula for sum(1, n) */
}
int main()
{
cout << calcMissing(new int[4]{3, 4, -1, 1}, 4) << endl;
cout << calcMissing(new int[3]{1, 2, 0}, 3) << endl;
//No positive numbers
cout << calcMissing(new int[1]{0}, 1) << endl;
}