Differences between C and C++:

Differences between C and C++:

1) When a function takes no parameter, its prototype has the word void inside parenthesis.

int fun(void);

However, in C++ the void is optional.

int fun();

If this convention would use in C, it mean that nothing is said about the parameters.

2) In a C++ program, all functions must be prototyped. In C, prototypes are recommended but technically optional.

3) About keyword return:

In C++, if a function is declared as returning a value, that is return type other than void, any return statement within that function must contain a value.

In C, a non void function is not required to actually return a value. If it doesn’t, a garbage value is returned.

4) Comments:

In C, comments in the program can be specified by /*….*/

In C++, due to backward compatibility, /*….*/ is still used for multiple line comments. We can also make a single line as comment by prefix that line by //

5) Declaration of local variables:

In C local variables can be declared only at the start of a block prior to any action statements.

In C++ local variables can be declared anywhere in the block.

6) Reference variable

In C++, reference variable are implicit pointers that acts as another variable name for some existing variable. There is no concept of reference variable in C.

7) Top Down and Bottom up approach

C programmer follows top down approach for programming

It is a program design technique that starts with the highest level of an idea and works its way down to the lowest level of detail.

C++ programmer adopts bottom up approach for programming.

In a bottom-up approach the individual base elements of the system are first specified in great detail. These elements are then linked together to form larger subsystems, which then in turn are linked, sometimes in many levels, until a complete top-level system is formed.

8) Procedure oriented Programming and Object Oriented Programming

Procedure oriented Programming:

Main program is divided into small parts depending on the functions.

The Different part of the program connects with each other by parameter passing. Most of the functions use global data.

Object Oriented Programming:

Main program is divided into small objects depending on the problem.

Data & functions of each individual object act like a single unit.

Each object controls its own data.

Data hiding is possible in OOP which prevent illegal access of function from outside of it. This is one of the best advantages of OOP.