Here I will begin my large C++ tutorial that many people have been asking for. I decided to teach C++ through problem solving. This first video covers preprocessor directives, main, cout, if, terminal arguments, for, data types, variables, constants, printf, strings, getline, cin, conversions, and much more.
This tutorial is light on problems, but for each forward I’ll try to include at least 3 progressively complex problems for you to solve. I hope you enjoy it.
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Transcript / Cheat Sheet
// ---------- 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 —————