Basic Data Types

There are basic four data types

1. char
2. int
3. float
4. double

A variable type char is 8 bits long and can hold a character.

A variable type int holds number with no fraction.(int came from the word integer). In 16 bit environment it can hold numbers valued from -32768(to keep in mind easily by (2)^(16-1) ) to + 32768. In 32 bits environment it can hold numbers valued form -2147483648(=2^(32-1) ) to +2147483647.

A variable type float and double holds numbers with fraction. The difference between float and double is that double can hold number valued twice larger than float.

  

Control Statement

control Statements are used to create special programme features such as logical test, loopoing and branches. An example of control statement is 

    for(i=0;i<=n;i++)
    { sum+=i }

This means that "i" is a number which starts from 0 and ends at a number "n" which may be given to computer manually and "sum+=i" means computer has to sum present value of i with the previous.For example 
         for i=0   sum=0
         for i=1   sum=0+1=1
         for i=2   sum=1+2=3
         for i=3   sum=3+3=6
         for i=4   sum=6+4=10 and so on.

Note:- Here "sum" itself does not means to sum a value. It is used to keep in mind easily. It can be written in other format as "x+=i".      

Compound Statement

A compound statement consists of several statements enclosed in a pair of second brackets. Such as-

    {cin>>a;
     sum=a+b;
     cout<<sum;}

Each statement of a compound statement can be expression statement, compound statement and control statement.

Expression Statement

An expression statement consists of an expression followed by a semicolon. Such as

   cin>>a>>b;

Note:- cin and cout are used in C++ but they can be used in C programming and easier to use than scanf and printf. 

Statement

Statements are those which direct computer to carryout actions. Statements are of three types --

1.Expression Statement

2.Compound Statement

3.Control Statement