C++ : C++ Basic Concepts
By Maria Zapata
Important Features : Important Features C++ is built upon foundation of C.
C++ was created to produce high performance for a specific type of CPU and operating system.
C++ is the parent of JAVA. How C++ relates to Java?
Slide 3 : The main difference between C++ and Java is the type of environment for which each is designed.
Java create portable programs and C++ can’t do the same because of the type of object code produced by the compiler.
In the case of C++, the output from the compiler is machine code.
Java compiles a program into a pseudocode, which is executed by a runtime system(JVM).
Slide 4 : Therefore, a Java program can run in any environment for which a JVM is available.
Since the Java runtime systems stand between a program and CPU, the java programs are slower than the C++ programs.
Java was developed in response to the unique programming needs of the online environments of the Internet, which is connected to many different types of CPU.
If you want to create high-performance software, use C++. If you need to create highly portable software, use Java.
My first program : My first program #include
using namespace std;
int main()
{
int thisisanumber;
cout<<“Please enter a number : “;
cin>>thisisanumber;
cout<<“You entered : “<Slide 6 :
How does it work? : How does it work? #include
using namespace std;
int main()
{
int thisisanumber;
cout<<“Please enter a number : “;
cin>>thisisanumber;
cout<<“You entered : “<Variables : Variables ALL VARIABLES MUST BE DECLARED BEFORE THEY ARE USED
Common types:
int (range -32,768 through 32,767)
float, double
char
Restrictions for variables:
Must start with a letter (sometimes they may start with underline character _).
They cannot match any C++ keyword
Very important: The C++ language is a "case sensitive" language.
Using an Operator : Using an Operator C++ supports a full range of arithmetic operators :
+ Addition
- Substraction
* Multiplication
/ Division
These operators work in C++ just like they do in algebra.
The following program uses the operator * to compute the area of a rectangle given its length and the width: : The following program uses the operator * to compute the area of a rectangle given its length and the width: //Using an operator
#include
using namespace std;
int main()
{
int length;
int width;
int area;
length = 7;
width = 5;
area = length * width;
cout << “The area is “<Fundamental Data Types : Fundamental Data Types
An interactive program : An interactive program #include
using namespace std;
int main()
{
int length;
int width;
cout<<“Enter the length : “;
cin >>length;
cout<<“Enter the width : “;
cin >>width;
cout<<“The area is “<Program that converts feet to meters : Program that converts feet to meters #include
using namespace std;
int main()
{
double f;
double m;
cout <<“Enter the length in feet : “;
cin >> f;
m = f / 3.28;
cout << f << “feet is “ << m << “ meters.”;
}
Here is a sample run:
Enter the length in feet : 5 5 feet is 1.52439 meters.