Hochiminh University of Technology
Computer Science and Engineering - [CO1011 - 501127]

Fundamentals of
C++ Programming

Basic components
in C/C++
Lecturer: Dustin Nguyen, PhD.


Outcomes
❖

Be able to explain the source code using comments

❖

Writing clear code with indent and rules

2


“C makes it easy to shoot yourself in the foot; C++ makes it harder,
but when you do, it blows away your whole leg.”
– Bjarne Stroustrup


Today’s outline
❖

Program structure

❖

Data types and operators

❖

Variable declarations

❖

Integers

❖

Problem solving

4


Program structure


Program structure
❖

Example

#include <iostream>

#include <string>
using namespace std;
int main() {
string name = "";
cout << “Login (please input your name): “ << endl;
getline(cin, name);
cout << "Hello " << name << “! Welcome to C++ world.” << endl;
return 0;
}

#include <stdio.h>
int main() {
char name[20] = "";
printf(“Login (please input your name): “);
gets(name);
printf(“Hello %s! Welcome to C world\n.", name);
return 0;
}
6


Program structure
❖

Preprocessing directive: anything begin with #
❖

define, undef, etc.: constant, macros

❖


include: source inclusion (use libraries or additional code)

❖

pragma: specify diverse options for compiler

❖

namespace: use to group components of a module, library, or a pack of smaller
libraries.

❖

main(): the entry point of our program. This is where everything start.
7


Program structure
❖

Global variables definition: these variable are visible to all classes and
functions in the program
❖

Scope: global vs. local

❖

Different between C and C++ in variable declaration


❖

Statements: instructions, operations, variable declarations, or a call to other
functions. Each statement ends with “;”

❖

Structure vs. Class definition and implementation

8


Program structure
❖

Another example
#include <iostream>
#include <string>
int main(int narg, char* argv[]) {
std::cout << “******************************************************”
std::cout << “*
This is an example of C++ program
*”
std::cout << “* It does nothing but print this text on the screen. *”
std::cout << “* Observe the difference between this code and the
*”
std::cout << “* previous code. What is the difference?
*”
std::cout << “******************************************************”

return 0;
}

9

<<
<<
<<
<<
<<
<<

std::endl;
std::endl;
std::endl;
std::endl;
std::endl;
std::endl;


Program structure
❖

Simple template
#include <something>
// define data structure
// define functions
// declare global variables
int main(int narg, char* argv[]) {
// local variables

/* Your code should be put here.
* Remember that in C++ you can declare variables where you need it.
* However, it is not good to declare variables that way since it
* is hard to maintenance, modify, and expand your code in the future.
* You should consider the scope of your variables before you declare
* them.
*/
return 0;
}

10


Comments
❖

Two types
❖

Single line comments: anything after //
❖

❖

a = 0; // set variable a to 0

Block comments: anything between /* and */
❖

b = 1; /* set b to 1.


remember that the value variable b 

can be changed later */ c = -1;

11


Indents, coding style
❖

❖

Use indents to enhance your code
❖

Easy to manage flow of code

❖

Easy to read code

Coding requires skills and the programmer, in most of cases need to follow
rules of their community.

12


Compile the program
❖

Simplest way: using IDE

❖

❖

Visual Studio, Xcode, KDE IDE, Eclipse, etc.

Manually: gcc, g++
❖

gcc example.c

❖

g++ example.cpp

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Compile and link separately

❖

Use other build system: e.g. CMake
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Data types and operators


Data types and operators
#include <iostream>

#include <string>
using namespace std;
int main() {
string name = "";
cout << “Login (please input your name): “ << endl;
getline(cin, name);
cout << "Hello " << name << “! Welcome to C++ world.” << endl;
return 0;
}
#include <iostream>
#include <string>
int main(int narg, char* argv[]) {
std::cout << “******************************************************”
std::cout << “*
This is an example of C++ program
*”
std::cout << “* It does nothing but print this text on the screen. *”
std::cout << “* Observe the difference between this code and the
*”
std::cout << “* previous code. What is the difference?
*”
std::cout << “******************************************************”
return 0;
}
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<<
<<
<<
<<

<<
<<

std::endl;
std::endl;
std::endl;
std::endl;
std::endl;
std::endl;


Data types and operators
❖

Basic data types
❖

Numeric types: integer, floating-point data

❖

Character/String: character, array of characters, struct/class

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Boolean: true/false

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Structure/Class: defined by user, fully customized


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Enum: names associated with integer values

❖

auto: must be associated with an assignment operation (only in modern C++)

16


Data types and operators
❖

❖

Basic operators
❖

=: assignment. E.g.: x = 8;

❖

+, -, *, /, %, etc. : arithmetic operators. E.g.: a = a + b - 5;

❖

^, ~, &, |, >>, <<: bitwise operators. E.g.: a = a^b;


❖

!, &&, ||, >, <, ==, etc. : logic operators. E.g.: b = a && c || (!a);

Other operators
❖

<<, >>, ::, ?:, ., etc.

17


Data types and operators
❖

Compound assignments:
❖

+=, -=, *=, /=, %=

❖

>>=, <<=, &=, !=, ^=

❖

a <op>= b is equivalent to a = a <op> b
❖

E.g.: x += 8;// equivalent to x = x + 8


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Data types and operators
❖

Example
#include <iostream>
#include <string>
using namespace std;
int main() {
int x, y, ret;
cout << “Input x: ”;
cin >> x;
cout << “Input y: ”;
cin >> y;
cout << “x + y = ” << x + y << endl;// compute value inside statement
/* use another variable to hold the result
* before print it on screen */
ret = (x - y) * (x + y);
cout << “x*x - y*y = ” << ret << endl;
cout << “x mod y = ” << x % y << endl;
return 0;
}

19


Variable declaration



Variable declaration
❖

[optional] <type> <variable name>[<array declaration>][=assigned values]
❖

int i, j;

❖

float x = 0.5f;

❖

const char* depName = “BK-CSE”;

❖

volatile int noOpt = 100;

❖

etc.

21


Variable declaration

❖

Rules for variable name (identifiers, in general):
❖

A valid identifier is a sequence of one or more letters, digits, or underscore characters (_).

❖

Spaces, punctuation marks, and symbols cannot be part of an identifier.

❖

Identifiers shall always begin with a letter/_.

❖

Case sensitive

❖

Reserved keywords:
❖

alignas, alignof, and, and_eq, asm, auto, bitand, bitor, bool, break, case, catch, char, char16_t,
char32_t, class, compl, const, constexpr, const_cast, continue, decltype, default, delete, do, double,
dynamic_cast, else, enum, explicit, export, extern, false, float, for, friend, goto, if, inline, int,
long, mutable, namespace, new, noexcept, not, not_eq, nullptr, operator, or, or_eq, private, protected,
public, register, reinterpret_cast, return, short, signed, sizeof, static, static_assert, static_cast,
struct, switch, template, this, thread_local, throw, true, try, typedef, typeid, typename, union,

unsigned, using, virtual, void, volatile, wchar_t, while, xor, xor_eq

22


Variable declaration
❖

Example

#include <iostream>
#include <string>
#include <stdio.h>
using namespace std;
int main() {
char name[50] = “”;
int
age;// user age
float height;
bool isStudent = false;// this flag is true if this is a student
cout << “Please input your name: ”;
gets(cin, name);
cout << “How old are you? ”;
cin >> age;
cout << “How tall are you? ”;
cin >> height;
cout << “Are you a student?”;
// process more...
return 0;
}

23


Assignment statement
❖

<left operand> = <expression>;

❖

return <left operand>

❖

<left operand> can’t be constant

❖

Example:
❖

pi = 3.1415;

❖

keyPressed = ‘q’;

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Assignment statement
❖

At declaration time:
❖

❖

int x = 10;

Other syntaxes
❖

int y{8};

❖

AnimalC monkey(10.5, 30);

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