1. Lecture 03
C++ Programming Basics
Comparison between C++ & C:
i) input/output statement
ii) data type
iii) arithmetic operators
iv) header files

2. C++ vs C
C++ is a superset of C.
C++ was originally called “C with classes”.

3. Basic C++ Program Construct

4. Basic C++ Program Construct
A Sample Program
// first.cpp
#include <iostream>
//preprocessor
using namespace std; //directive
int main()
{
int ftemp; // temperature in Fahrenheit
cout << "Enter temperature in Fahr.: ";
cin >> ftemp;
int ctemp = (ftemp - 32) * 5 / 9;
cout << "Equivalent in Celsius is: "
<< ctemp << endl;
return 0;

5. Comments
C Style:
/* This program demonstrate
function overloading */
C++ Style:
// This program demonstrate
// function overloading

6. Preprocessor Directive
#include
C Style:
#include<stdio.h>
C++ Style:
#include<iostream.h>
OR THE FOLLOWING ANSI STANDARD
#include<iostream>
using namespace std;

7. Input and Output
C Input and Ouput:
#include<stdio.h>
scanf(“%i”, &num);
printf(“The number is %in“, num);
C++ Input and Ouput:
#include<iostream.h>
cin >> num;
cout << “The number is “, num << endl;

8. Stream I/O
Insertion and Extraction

9. Constants
C-Style Symbolic Constant:
#define PI 3.14159
We can’t specify the data type!
What is a Variable ?
C++ const Qualifier: What is an
const float PI = 3.14159; Identifier?
Rules for declaring
an identifier?
Recommended !
Int Sum1 ;
Float 1Salaray

10. Boolean Type
• Integer, character, and floating-point types are available
both in C and C++.
• Boolean type is available in C++, but not in C.
• Variables of type bool can have only two possible
values: true and false (Boolean Values).
• Even though a single bit is enough to store variables of
type bool, compilers often store them as integers for
ease of processing.

11. Boolean Type
Void Main( )
{ int num; bool flag = true;
void main()
Cin>> num;
{
if (num > 0 )
bool flag = true;
flag = true;
else
if (flag) flag = false;
cout<<“Hello Halizah”<<endl; if (flag == true )
cout<<“positive
else number”;
cout<<“Hello World!”<<endl; else
} cout “negative
number”;
}

12. Type Conversion : Order of Data Types
Data Type Order
long double Highest
double
float
long
int
short
char Lowest

13. Automatic Type Conversion
• When two operands of different types are encountered in
the same expression, the lower-type variable is
automatically converted to the higher type variable.
int denominator;
float numerator, quotient;
...
quotient = numerator/denominator;
• denominator is converted from int to float before
the division.

14. The setw Manipulator
#include <iostream.h>
#include <iomanip.h> // for setw
int main()
{
long pop=2425785;
cout << setw(8) << "LOCATION" << setw(12)
<< "POPULATION" << endl
<< setw(8) << "Portcity" << setw(12) << pop
<< endl
return 0;
}
Output of the program:
LOCATION POPULATION
Portcity 2425785

15. The <cmath>
Standard Library Functions
// sqrt.cpp
// demonstrate sqrt() library function
#include <iostream> // for cout, etc.
#include <cmath> // for sqrt()
using namespace std;
int main()
{
double number, answer;
cout << "Enter a number: ";
cin >> number;
answer = sqrt(number);
cout << "Square root is " << answer << endl;
return 0;
}

16. Header and Library Files