Lecture 03 C++ Programming Basics
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Transcript of Lecture 03 C++ Programming Basics
Lecture 03
C++ Programming Basics
Comparison between C++ & C:i) input/output statementii) data typeiii) arithmetic operatorsiv) header files
C++ vs C
C++ is a superset of C. C++ was originally called “C with classes”.
Basic C++ Program Construct
Basic C++ Program ConstructA Sample Program
// first.cpp #include <iostream> //preprocessorusing 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; }
Comments
C Style:
/* This program demonstrate
function overloading */
C++ Style:
// This program demonstrate
// function overloading
Preprocessor Directive#include
C Style:
#include<stdio.h>
C++ Style:
#include<iostream.h>
OR THE FOLLOWING ANSI STANDARD
#include<iostream>
using namespace std;
Input and Output
C Input and Ouput:
#include<stdio.h>
scanf(“%i”, &num);
printf(“The number is %i\n“, num);
C++ Input and Ouput:
#include<iostream.h>
cin >> num;
cout << “The number is “, num << endl;
Stream I/OInsertion and Extraction
Constants
C-Style Symbolic Constant:
#define PI 3.14159
We can’t specify the data type!
C++ const Qualifier:
const float PI = 3.14159;
Recommended !
What is a Variable ?
What is an Identifier?
Rules for declaring an identifier?
Int Sum1 ;Float 1Salaray
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.
Boolean Type
void main()
{
bool flag = true;
if (flag)
cout<<“Hello Halizah”<<endl;
else
cout<<“Hello World!”<<endl;
}
Void Main( )
{ int num; bool flag = true;
Cin>> num;
if (num > 0 )
flag = true;
else
flag = false;
if (flag == true ) cout<<“positive number”;
else
cout “negative number”;
}
Type Conversion : Order of Data Types
Data Type Order
long double Highestdoublefloatlongintshortchar Lowest
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.
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
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; }
Header and Library Files