Statements:
A
statement in C is the smallest unit executed by the C compiler that causes the
compiler to carry out some action. Every statement must end with a semicolon. A
program can contain more than one statement. If a program contains more than
one statement then they are executed sequentially i.e. the order in which they
specified. However, it is also possible to group a sequence of statements by
enclosing them into pair of braces; such group of statements is referred as the
statement block. The statement block can be named or provided a condition for
execution.
There
are various type of statements available in C which can be categorized as
shown:
Empty Statement:
An
empty statement in C is written as a single semicolon (;). It does not do
anything but sometimes they are very useful.
Expression Statement:
Expression
statements are expressions that end with a semicolon. Most statements in a
program are expression statements. These include assignment statements, prefix
or postfix statements.
Control Statements:
Control
statements change the sequential order of the execution by using selection,
iteration and transfer statements. These statements can be classified as follows:
a) Selection Statements: These statements allow the
execution of a block of statements depending upon the value of the Boolean
expression or selection among several statements based on the value of Boolean
expression or control variable. These statements include if, if- else and
switch statements.
b)
Iteration Statements: These statements allow a statement or a block of statements to be executed repeatedly and have a loop control mechanism that determines how many times the block of statements will execute. These statements include while, do- while and for statements.
Iteration Statements: These statements allow a statement or a block of statements to be executed repeatedly and have a loop control mechanism that determines how many times the block of statements will execute. These statements include while, do- while and for statements.
c)
Transfer Statements: These statements transfer control to the beginning of the block, end of the block. These include continue, break, return and goto statements.
Transfer Statements: These statements transfer control to the beginning of the block, end of the block. These include continue, break, return and goto statements.
There are certain rules applicable to all C statements:
i)
Every statement in C always ends with a semicolon (;);
ii)
Usually all statements are written in small case letters.
iii)
Blank spaces may be inserted between two words to improve the
readability of the statement. However, no blank spaces is allowed with a
variable, constant or keyword.
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