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Apr 30, 2021rlbishop99
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Two Letter Combinations

Nov 18, 2022AustinLeath

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#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
using namespace std;
//This program makes a new text file that contains all combinations of two letters.
// aa, ab, ..., zy, zz
int main(){
string filename = "two_letters.txt";
ofstream outFile;
outFile.open(filename.c_str());
if(!outFile.is_open()){
cout << "Something's wrong. Closing..." << endl;
return 0;
}
for(char first = 'a'; first <= 'z'; first++){
for(char second = 'a'; second <= 'z'; second++){
outFile << first << second << " ";
}
outFile << endl;
}
return 0;
}

Compute Volume of Cylinder

Nov 18, 2022AustinLeath

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/*
Algorithm:
Step 1: Get radius of the cylinder from the user and store in variable r
Step 2: Get height of the cylinder from the user and store in variable h
Step 3: Multiply radius * radius * height * pi and store in v
Step 4: Display the volume
*/
#include <iostream>
using namespace std;
int main()
{
float r; //define variable for radius
float h; //define variable for height
float v;
float pi;
pi=3.1416;
cout<<"Enter radius:";
cin>>r;
cout<<"Enter height:";
cin>>h;
v=r*r*h*pi; //compute volume
cout<<"Radius:"<<r<<"\tHeight:"<<h<<endl; //display radius and height
cout<<"\n************************\n";
cout<<"Volume:"<<v<<endl;//display volume
return 0;
}

Audio Frequency Amplitudes

Aug 27, 2021LeifMessinger

0 likes • 1 view

//From https://create.arduino.cc/projecthub/abhilashpatel121/easyfft-fast-fourier-transform-fft-for-arduino-9d2677
#include <cmath>
#include <iostream>
const unsigned char sine_data[] = { //Quarter a sine wave
0,
4, 9, 13, 18, 22, 27, 31, 35, 40, 44,
49, 53, 57, 62, 66, 70, 75, 79, 83, 87,
91, 96, 100, 104, 108, 112, 116, 120, 124, 127,
131, 135, 139, 143, 146, 150, 153, 157, 160, 164,
167, 171, 174, 177, 180, 183, 186, 189, 192, 195, //Paste this at top of program
198, 201, 204, 206, 209, 211, 214, 216, 219, 221,
223, 225, 227, 229, 231, 233, 235, 236, 238, 240,
241, 243, 244, 245, 246, 247, 248, 249, 250, 251,
252, 253, 253, 254, 254, 254, 255, 255, 255, 255
};
float sine(int i){ //Inefficient sine
int j=i;
float out;
while(j < 0) j = j + 360;
while(j > 360) j = j - 360;
if(j > -1 && j < 91) out = sine_data[j];
else if(j > 90 && j < 181) out = sine_data[180 - j];
else if(j > 180 && j < 271) out = -sine_data[j - 180];
else if(j > 270 && j < 361) out = -sine_data[360 - j];
return (out / 255);
}
float cosine(int i){ //Inefficient cosine
int j = i;
float out;
while(j < 0) j = j + 360;
while(j > 360) j = j - 360;
if(j > -1 && j < 91) out = sine_data[90 - j];
else if(j > 90 && j < 181) out = -sine_data[j - 90];
else if(j > 180 && j < 271) out = -sine_data[270 - j];
else if(j > 270 && j < 361) out = sine_data[j - 270];
return (out / 255);
}
//Example data:
//-----------------------------FFT Function----------------------------------------------//
float* FFT(int in[],unsigned int N,float Frequency){ //Result is highest frequencies in order of loudness. Needs to be deleted.
/*
Code to perform FFT on arduino,
setup:
paste sine_data [91] at top of program [global variable], paste FFT function at end of program
Term:
1. in[] : Data array,
2. N : Number of sample (recommended sample size 2,4,8,16,32,64,128...)
3. Frequency: sampling frequency required as input (Hz)
If sample size is not in power of 2 it will be clipped to lower side of number.
i.e, for 150 number of samples, code will consider first 128 sample, remaining sample will be omitted.
For Arduino nano, FFT of more than 128 sample not possible due to mamory limitation (64 recomended)
For higher Number of sample may arise Mamory related issue,
Code by ABHILASH
Documentation:https://www.instructables.com/member/abhilash_patel/instructables/
2/3/2021: change data type of N from float to int for >=256 samples
*/
unsigned int sampleRates[13]={1,2,4,8,16,32,64,128,256,512,1024,2048};
int a = N;
int o;
for(int i=0;i<12;i++){ //Snapping N to a sample rate in sampleRates
if(sampleRates[i]<=a){
o = i;
}
}
int in_ps[sampleRates[o]] = {}; //input for sequencing
float out_r[sampleRates[o]] = {}; //real part of transform
float out_im[sampleRates[o]] = {}; //imaginory part of transform
int x = 0;
int c1;
int f;
for(int b=0;b<o;b++){ // bit reversal
c1 = sampleRates[b];
f = sampleRates[o] / (c1 + c1);
for(int j = 0;j < c1;j++){
x = x + 1;
in_ps[x]=in_ps[j]+f;
}
}
for(int i=0;i<sampleRates[o];i++){ // update input array as per bit reverse order
if(in_ps[i]<a){
out_r[i]=in[in_ps[i]];
}
if(in_ps[i]>a){
out_r[i]=in[in_ps[i]-a];
}
}
int i10,i11,n1;
float e,c,s,tr,ti;
for(int i=0;i<o;i++){ //fft
i10 = sampleRates[i]; // overall values of sine/cosine :
i11 = sampleRates[o] / sampleRates[i+1]; // loop with similar sine cosine:
e = 360 / sampleRates[i+1];
e = 0 - e;
n1 = 0;
for(int j=0;j<i10;j++){
c=cosine(e*j);
s=sine(e*j);
n1=j;
for(int k=0;k<i11;k++){
tr = c*out_r[i10 + n1]-s*out_im[i10 + n1];
ti = s*out_r[i10 + n1]+c*out_im[i10 + n1];
out_r[n1 + i10] = out_r[n1]-tr;
out_r[n1] = out_r[n1]+tr;
out_im[n1 + i10] = out_im[n1]-ti;
out_im[n1] = out_im[n1]+ti;
n1 = n1+i10+i10;
}
}
}
/*
for(int i=0;i<sampleRates[o];i++)
{
std::cout << (out_r[i]);
std::cout << ("\t"); // un comment to print RAW o/p
std::cout << (out_im[i]); std::cout << ("i");
std::cout << std::endl;
}
*/
//---> here onward out_r contains amplitude and our_in conntains frequency (Hz)
for(int i=0;i<sampleRates[o-1];i++){ // getting amplitude from compex number
out_r[i] = sqrt(out_r[i]*out_r[i]+out_im[i]*out_im[i]); // to increase the speed delete sqrt
out_im[i] = i * Frequency / N;
std::cout << (out_im[i]); std::cout << ("Hz");
std::cout << ("\t"); // un comment to print freuency bin
std::cout << (out_r[i]);
std::cout << std::endl;
}
x = 0; // peak detection
for(int i=1;i<sampleRates[o-1]-1;i++){
if(out_r[i]>out_r[i-1] && out_r[i]>out_r[i+1]){
in_ps[x] = i; //in_ps array used for storage of peak number
x = x + 1;
}
}
s = 0;
c = 0;
for(int i=0;i<x;i++){ // re arraange as per magnitude
for(int j=c;j<x;j++){
if(out_r[in_ps[i]]<out_r[in_ps[j]]){
s=in_ps[i];
in_ps[i]=in_ps[j];
in_ps[j]=s;
}
}
c=c+1;
}
float* f_peaks = new float[sampleRates[o]];
for(int i=0;i<5;i++){ // updating f_peak array (global variable)with descending order
f_peaks[i]=out_im[in_ps[i]];
}
return f_peaks;
}
//------------------------------------------------------------------------------------//
//main.cpp
int data[64]={
14, 30, 35, 34, 34, 40, 46, 45, 30, 4, -26, -48, -55, -49, -37,
-28, -24, -22, -13, 6, 32, 55, 65, 57, 38, 17, 1, -6, -11, -19, -34,
-51, -61, -56, -35, -7, 18, 32, 35, 34, 35, 41, 46, 43, 26, -2, -31, -50,
-55, -47, -35, -27, -24, -21, -10, 11, 37, 58, 64, 55, 34, 13, -1, -7
};
int main(){
const unsigned int SAMPLE_RATE = 48*1000; //48khz
auto result = FFT(data,64,SAMPLE_RATE);
std::cout << result[0] << " " << result[1] << " " << result[2] << " " << result[3] << std::endl;
delete[] result;
return 0;
}

C++ Range Slicer

Oct 31, 2023LeifMessinger

0 likes • 3 views

//Leif Messinger
//Compile with C++ 20
#include <iostream>
#include <ranges>
#include <vector>
#include <functional>
#include <cctype> //toupper
#include <cxxabi.h>
template <typename T>
void printType(){
std::cout << abi::__cxa_demangle(typeid(T).name(), NULL, NULL, NULL) << std::endl;
}
template <typename T>
class Slicer{
public:
T begin_;
T end_;
T trueEnd;
Slicer(T begin, T end): begin_(begin), end_(begin), trueEnd(end){}
template<typename U>
Slicer(U&& vec) : begin_(vec.begin()), end_(vec.begin()), trueEnd(vec.end()){}
Slicer& finish(){
begin_ = end_;
end_ = trueEnd;
return (*this);
}
Slicer& to(long int index){
begin_ = end_;
if(index > 0){
end_ = (begin_ + index);
}else{
index *= -1;
end_ = (trueEnd - index);
}
return (*this);
}
Slicer& operator[](long int index){
return to(index);
}
T begin(){
return this->begin_;
}
T end(){
return this->end_;
}
Slicer& operator()(std::function<void(decltype(*begin_))> func) {
for(decltype(*begin_) thing : (*this)){
func(thing);
}
return (*this);
}
};
static_assert(std::ranges::range< Slicer<std::vector<int>::const_iterator> >);
int main(){
std::string vec = "abcdefghijklmnopqrstuvwxyz";
Slicer<std::string::const_iterator> bruh(vec);
//printType<decltype(bruh)>();
bruh.to(3)([](char yeet){
std::cout << yeet;
})
.to(-1)([](char yeet){
std::cout << char(std::toupper(yeet));
}).finish()([](char yeet){
std::cout << yeet << yeet << yeet << yeet << yeet;
});
std::cout << std::endl << std::endl;
int arr[] = {1, 2, 3, 4, 5, 6, 7, 8};
Slicer<int*> arrSlicer(arr, arr + (sizeof(arr)/sizeof(int)));
std::cout << "[";
arrSlicer.to(-1)([](int yeet){
std::cout << yeet << ", ";
}).finish()([](int yeet){
std::cout << yeet << "]" << std::endl;
});
return 0;
}

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;
}

Enumeration Basics

Nov 18, 2022AustinLeath

0 likes • 10 views

#include <iostream>
using namespace std;
/*
Description: uses switch case statements to determine whether it is hot or not outside.
Also uses toupper() function which forces user input char to be uppercase in order to work for the switch statement
*/
int main() {
char choice;
cout << "S = Summer, F = Fall, W = Winter, P = Spring" << endl;
cout << "Enter a character to represent a season: ";asdasdasdasd
cin >> choice;
enum Season {SUMMER='S', FALL='F', WINTER='W', SPRING='P'};
switch(toupper(choice)) // This switch statement compares a character entered with values stored inside of an enum
{
case SUMMER:
cout << "It's very hot outside." << endl;
break;
case FALL:
cout << "It's great weather outside." << endl;
break;
case WINTER:
cout << "It's fairly cold outside." << endl;
break;
case SPRING:
cout << "It's rather warm outside." << endl;
break;
default:
cout << "Wrong choice" << endl;
break;
}
return 0;
}