C++ Programming Lecture 1

Why C++?

I'm on my journey to pursuing my Master's in CS! Along with taking the GRE and obtaining letters of rec, I also must take a handful of prerequisites that my Computational Mathematics major didn't include.

Today marked the start of my C++ Programming course. So why are we learning C++ instead of let’s say Python or Java? While this question wasn’t answered in my first lecture, I would like to highlight a few points:

1. C++ is more similar to C and requires manual memory management.
2. C++ supports Object Oriented Programming (OOP)

Since both Python and Java support OOP, I’d imagine that the main selling point is C++’s low-level programming capabilities. Higher-level languages abstract memory management, so C++ forces us to efficiently manage it ourselves.

Side-note: It’s really convenient that most C code can also be run as a C++ program.

Now back to my class activities.

Components of a C++ Program

We took a look at a particular code segment and were introduced to the basic components of a C++ program. Afterward, we were asked to make a few edits for an in-class assignment.

The following code snippet is as follows

#include <iostream>
using namespace std;

int main() {
    int totalInches;
    int totalFeet;
    int totalMiles;
    int remainingFeet;
    int remainingInches;
    cout << "Please enter the total number of inches: ";

    cin >> totalInches;


    totalFeet = totalInches / 12;
    totalMiles = totalFeet / 5280;
    remainingFeet = totalFeet % 5280;
    remainingInches = totalInches % 12;

    cout << totalInches << " inch(es) is equal to "
         << totalMiles << "mile(s),"
         << remainingFeet << " feet and "
         << remainingInches << " inch(es)."
         << endl << endl;

    cout << "Bye Now!" << endl;
    return 0;
}

Let’s break down each unfamiliar keyword and operator.

General

• #include - a directive that tells the compiler to include contents of a specified file. The preprocessor replaces the line with #includes with the actual code located in the header file
• header file - any file that contains C-language functions. May be included in other existing C files
• namespace - an area that defines the scope of all things (functions + variables) inside it. It’s much like adding curly braces {} around a whole region of code and calling it a name.
• int main() - defines our main program that all other functions are called from
  • Standard practice is to specify an int return value and to return 0 on finish

IoStream + std

• std - namespace for the C++ standard library that holds many useful classes and functions
  • cout - used to print characters to the console. stands for “character output”. part of std
  • cin - used to get input from the user. stands for “character input”. part of std
  • endl - used to print a newline “\n” to the console and flushes the output buffer (AKA all data is written to the output device in that instant)
• “using namespace std;” - allows us to define things like cout without having to write the full std::cout statement
• iostream - a file that includes functions that allow for input and output operations using streams (streams - flow of data in or out of a program)
  • printing to the console
  • printing an error message
• << operator - used for outputting data onto the stream. Usually used to push data into the cout output stream
• >> operator - used for getting input data from the stream. Usually used to pull user inputted data from the stream into a variable via cin

And that’s all for the first day! I’m looking forward to furthering my understanding of computer programs as this course progresses