I/O File Handling in C++ (OOPs)

A File is a bunch of bytes stored on some storage device like magnetic disk or tape etc. Most of the application programs process large volume of data which is permanently stored in files. We can write programs that can read data from file(s) and write data to file(s). 

Polymorphism in C++ (OOPs)

Polymorphism is made from two words POLY+MORPHISM which means more the one form. In C++ polymorphism is implemented by overloading a function or an operator. In Function Overloading a single function name is used to perform different tasks. 

Inheritance in C++ (OOPs)

It is the process by which objects of one class acquire the properties of objects of another class. The old class is referred as Base CLASS and the class that inherits the Base Class if Derived CLASS. 

Constructors & Destructors in C++ (OOPs)

In C++, a class only creates a data type and the objects of a class are created and initialized as separate. A constructor (having the same name as that of a CLASS) is a member function which is automatically used to initialize the objects of the CLASS type with legal initial values.

Classes & Objects in C++ (OOPs)

“C with classes” was the original name given by the originator Stroustrup initially, which now days is popular known form as C++ or OOPs (Object Oriented Programming). Classes and objects are the most important feature of C++. The Class implements OOPs features and ties then together. We have already seen that a structure groups different types of elements and a function organizes the program actions to perform the desired task.

Loop Control- for loop in C++ (OOPs)

“for” loop is also structure control loop as program will run or execute if the initial condition is true otherwise it will terminate and program will run until some condition is fulfilled.

FORMAT:
for(expression1;expression2;expression3)
{
Statement1;
Statement2;
}

Switch Statement in C++ (OOPs)

This statement is also used for decision making. Here key word is switch followed by control variable and followed by it’s block.
In the block of switch statement multiple cases are used and each ends with break statement this is also called as early exit loop.
Out of all the cases only that case will run whose value matches with the control variable.

Loop Control- While & Do-while in C++ (OOPs)

These are used for repeating some portion of the program either by specified number of times or until a particular condition is true.
1. while statement
2. do while statement
3. for loop

Decision Making- Nested If else in C++ (OOPs)

This statement can be used to select any one statement or a block which contains a set of instructions. Only that statement will execute which is true according to the data entered and rest other conditions will not executed.

Decision Making- If else statement in C++ (OOPs)

This statement is also a conditional statement. It starts with keyword ‘if’ followed by an expression followed by “ first statement”  and “ second statement” is given after ‘else’ clause.

Format:
if(expression)
statement1;
else
statement2;

Decision Making- If statement in C++ (OOPs)

It is used whenever any condition is to be implemented by the user it means some conditions like:
1. If the price of the item is more than 5000 then discount is 10%.
2. If the students marks are greater than 60% then he should be in 1st division.

Simple C++ (OOPs) Programs

/* Program to enter two values and perform addition and multiplication operation*/

#include<iostream.h>
#include<conio.h>
main()
{
      int n1,n2,sum,mul;
      cout<<"\n Enter any two numbers";
      cin>>n1>>n2;
      sum=n1+n2;
      mul=n1*n2;
      cout<<"\n Sum of two numbers is "<<sum;
      cout<<"\n Multiplication of two numbers is "<<mul;
      getch();
}

Files Input/Output in C-language

A file is a place on the disk where the group of related data are stored. The first function is to be performed when we are accessing the files is to open a file. Opening a file establishes a link between the program and the operating system about which file we want to access for what purpose. We provide the operating system to which file we want to access and for what purpose. For accessing a file we just have to name the file and plan whether we want o read data from the file or write data onto the file. The syntax for opening is:

FILE *fp;
inbuilt structure
fp= fopen( “file name”, “mode”);

Call by Value and Reference

Prototype Function

When a function is defined after the main function it needs to be declared in the declaration section of the program. This declaration section statement is known as function prototype.
This tells the calling function the type of value that will be returned with the name of the function and list of argument data types.

Syntax:
return type  function name(Argument list);
int fun (f1,f2);

Function with parameter with return

This function can also return a value from the called function to the calling function i.e. the output which is printed in the main function whenever the value will be returned to the main function it can be printed thereafter. Now the function type should not be void because function will return a value. Therefore, it’s overall type is decided by the type of value it returned (int, float etc.).

Function without parameters in C-language

Such functions are defined same with return type followed by used defined name and a pair of parenthesis () and a block of codes. These functions uses two type of variables AUTOMATIC STORAGE CLASS VARIABLES and GLOBAL VARIABLES.

Simple C-programs

/*Program to enter two numbers by user and perform addition and multiplication operations*/

#include<stdio.h>
#include<conio.h>
void main()
{
     int n1,n2,sum=0,mul=0 ;
     printf("\n enter any two numbers");
     scanf("%d%d",&n1,&n2);
     sum=n1+n2;
     mul=n1*n2;
     printf("\n sum of two numbers is %d",sum);
     printf("\n multiplication of two numbers is %d",mul);
     getch();
     }

Operators in C and C++