C++ Part 1
// ---------- C++ Tutorial Example 1 ----------
/*
* Multi-line Comment
*/
// These are called preprocessor directives
// They load the files which contain premade functions
// for your use
// Contains functions for converting from 1 data type to
// another, random number generation, memory management,
// searching, math, sorting and other general purpose functions
#include <cstdlib>
// Provides functions for performing input and output operations
#include <iostream>
// If used you can type cout instead of std::cout
// By using this though you may have conflicts if you define
// functions that share a name with the std namespace
// using namespace std;
// You could define you only want to use part of a namespace like
// using std::cout;
// Which would allow you to use cout instead of std::cout
// Execution of code starts in the main function
// argc and argv is optional data that could be passed
// to the program if it was executed in a terminal
// argc : Number of arguments passed
// argv : Array pointers to strings
int main(int argc, char* argv[]) {
// Outputs the string Hello World to the screen followed by a newline
// cout is your console or screen
// << : Stream insertion operator which puts the string
// into the cout stream to display it
std::cout << "Hello World" << std::endl;
// If you compile the code into an executable program in the terminal
// g++ main.cpp
// And execute it : ./a.out I Love C++
// You'd see how to work with passed arguments
// If no arguments are passed argc has a value of 1
// We check that with if to skip printing values if none were passed
if(argc != 1){
// You can also create a newline with \n
std::cout << "You entered " << argc << " arguments\n";
// Cycles through all the values in the argc array and prints them
// We access the values by using their index number starting at
// 0
for(int i = 0; i < argc; ++i){
// We access each string passed by putting its index between []
// called the subscript operator
std::cout << argv[i] << "\n";
}
}
// When 0 is returned that signals that the program executed without
// an error and -1 signals an error occurred
return 0;
}
// ---------- End of C++ Tutorial Example 1 ----------
// ---------- C++ Tutorial Example 2 ----------
#include <cstdlib>
#include <iostream>
// Allows you to use the STL string class
#include <string>
// Provides functions to find min and max values
// for data types
#include <limits>
// When we create a variable we are telling the computer
// how much memory to set aside for its value and what
// name we want to associate with that data
// Variable names can contain letters, numbers, underscores
// but not math operators, spaces and can't start with a number
// Global variables are declared outside of any functions
// and can be accessed any where in the code
// This is a global integer variable with a name using
// Hungarian notation
int g_iRandNum = 0;
// const defines constant values that won't change
const double PI = 3.1415926535897932;
int main() {
// Get min and max values for different data types
// bools store true 1, or false 0
bool bMarried = true;
// char stores 256 single characters represented by your keyboard
char chMyGrade = 'A';
// unsigned short ints hold values from 0 to 65,535
// unsigned int & unsigned long int double their max value
unsigned short int u16Age = 43;
// short ints store between -32,768 to 32,767
short int siWeight = 180;
// ints range from -2147483648 to 2147483647
int nDays = 7;
// long ints and long long ints range from -9223372036854775808 to
// 9223372036854775807
long lBigNum = 1000000;
// floats range from 1.17549e-38 to 3.40282e+38
float fPi = 3.14159;
// Show float precision
float fBigFloat = 1.1111111111;
float fBigFloat2 = 1.1111111111;
float fFloatSum = fBigFloat + fBigFloat2;
// Allows you to print with formatting
// Float addition has 6 digits of precision
printf("fFloatSum Precision : %.10f\n", fFloatSum);
// doubles range from 2.22507e-308 to 1.79769e+308
std::cout << "Min double " <<
std::numeric_limits<double>::min() << "\n";
std::cout << "Max double " <<
std::numeric_limits<double>::max() << "\n";
// Show double precision
double dbBigFloat = 1.11111111111111111111;
double dbBigFloat2 = 1.11111111111111111111;
double dbFloatSum = dbBigFloat + dbBigFloat2;
// Allows you to print with formatting
// Double addition has 15 digits of precision
printf("dbFloatSum Precision : %.20f\n", dbFloatSum);
// long doubles range from 3.3621e-4932 to 1.18973e+4932
long double ldPi = 3.1415926535897932;
// You can have the compiler assign a type
auto whatWillIBe = true;
// SHOW DATA TYPES MIN & MAX VALUES
std::cout << "Min bool " << std::numeric_limits<bool>::min() << "\n";
std::cout << "Max bool " << std::numeric_limits<bool>::max() << "\n";
std::cout << "Min unsigned short int " <<
std::numeric_limits<unsigned short int>::min() << "\n";
std::cout << "Max unsigned short int " <<
std::numeric_limits<unsigned short int
>::max() << "\n";
std::cout << "Min short int " <<
std::numeric_limits<short int>::min() << "\n";
std::cout << "Max short int " <<
std::numeric_limits<short int
>::max() << "\n";
std::cout << "Min int " << std::numeric_limits<int>::min() << "\n";
std::cout << "Max int " << std::numeric_limits<int>::max() << "\n";
std::cout << "Min long " << std::numeric_limits<long int>::min() << "\n";
std::cout << "Max long " << std::numeric_limits<long int>::max() << "\n";
std::cout << "Min float " <<
std::numeric_limits<float>::min() << "\n";
std::cout << "Max float " <<
std::numeric_limits<float>::max() << "\n";
std::cout << "Min long double " <<
std::numeric_limits<long double>::min() << "\n";
std::cout << "Max long double " <<
std::numeric_limits<long double>::max() << "\n";
// Get the number of bytes used by a type
std::cout << "int Size " << sizeof(int) << "\n";
// More about printf()
// char, int, 5 space right justified int,
// 3 decimal float / double, string specifiers
printf("%c %d %5d %.3f %s\n", 'A', 10, 5, 3.1234, "Hi");
return 0;
}
// ---------- End of C++ Tutorial Example 2 ----------
// ---------- C++ Tutorial Example 3 ----------
#include <cstdlib>
#include <iostream>
#include <string>
int main() {
// Create a string
std::string sQuestion ("Enter Number 1 : ");
// Create empty strings to store values
std::string sNum1, sNum2;
std::cout << sQuestion;
// Receive user input and store it
getline(std::cin, sNum1);
std::cout << "Enter Number 2 : ";
getline(std::cin, sNum2);
// Convert from strings to int
// std::stod converts from strings to doubles
int nNum1 = std::stoi(sNum1);
int nNum2 = std::stoi(sNum2);
// Math Operators
printf("%d + %d = %d\n", nNum1, nNum2, (nNum1 + nNum2));
printf("%d - %d = %d\n", nNum1, nNum2, (nNum1 - nNum2));
printf("%d * %d = %d\n", nNum1, nNum2, (nNum1 * nNum2));
printf("%d / %d = %d\n", nNum1, nNum2, (nNum1 / nNum2));
printf("%d %% %d = %d\n", nNum1, nNum2, (nNum1 % nNum2));
// ----- PROBLEM : MILES TO KILOMETERS -----
// Sample knowing that kilometers = miles * 1.60934
// Enter Miles : 5
// 5 miles equals 8.0467 kilometers
// Create needed variables
std::string sMiles;
double dMiles, dKilometers;
// Ask user to input miles and store string input
std::cout << "Enter Miles : ";
getline(std::cin, sMiles);
// Convert from string to double
dMiles = std::stod(sMiles);
// Convert from miles to km
dKilometers = dMiles * 1.60934;
// Output the results
printf("%.1f miles equals %.4f kilometers\n", dMiles, dKilometers);
// ----- END PROBLEM : MILES TO KILOMETERS -----
return 0;
}
// ---------- End of C++ Tutorial Example 3 —————