CH04: Control Statement in C

Control Statements are used to control the flow of execution in a program based on certain conditions or values.

Two types of Control Statement:


If-else statement

If-else :

If-else statement is used to execute a statement block or a single statement depending on the value of a condition.

Syntax :

if (condition)
{
  ------------
  <true block>
  ------------
}
else
{
  -------------
  <false block>
  -------------
}

Where condition is a logical expression which will have the value of true or false.

Nested if-else statement

Nested if-else statement

An if statement may have another if statement in the true block and false block. This compound statement is called nested if statement.

Syntax :

if (condition 1)
{
  if (condition 2)
    {
        --------------
        <true block 1>
        --------------
    }
   else
    {
        -------------
        <false block 1>
        -------------
    }
}
else
{
  if (condition 3)
    {
      --------------
      <true block 2>
      --------------
    }
  else
    {
      ---------------
      <false block 2>
      ---------------
    }
}
Switch Statement

Switch statement

Switch statement is used to create a block of statements depending on the value of a variable or an expression.

Syntax :

switch ( <expression>)
{
case <label 1>: {
                  -------------
                  <statement block 1>
                  -------------
                  break;
                }
case <label 2>: {
                  -------------
                  <statement block 1>
                  -------------
                  break;
                }
case <label n>: {
                  -------------
                  <statement block n>
                  -------------
                  break;
                }
default:        {
                  -------------
                  <default statement block>
                  -------------
                  break;
                }
}

where <expression> refers to any int or char expression or variable.

<label 1>, <label 2>...<label n> are values which will match with the value of the expression.

break is a statement which will transfer the control to the end of switch statement.