Discussion of control statement

Control statement:::

THE IF…ELSE STATEMENT

The if….else statement is an extension of simple if statement.The general form is

If(test expression)

{

True-block statement(s)

}

else

{

False-block statement(s)

}

statement-x

If the test expression is true, then the true block statements are executed; otherwise

the false block statement will be executed

NESTING OF IF…..ELSE STATEMENTS

When a series of decisions are involved, we may have to use more than one if….else

statements, in nested form as follows.

If(test condition 1)

{

if(test condition 2)

{

statement-1;

}

else

{

statement-2;

}

}

else

{

statement-3;

}

Example::

Program

/*Selecting the largest of three values*/

main()

{

float A, B, C;

printf(“Enter three values \n”);

scanf(“|%f %f %f”,&A, &B, &C);

printf(“\nLargest value is:”);

if(A > B)

{ if(A > C)

printf(“%f \n”,A);

else

printf(“%f \n”,C);

}

else

{

if(C > B)

printf(“%f \n”,C);

else

printf(“%f \n”,B);

}

}

OUTPUT

Enter three values:

5 8 24

Largest value is 24

THE ELSEIF LADDER

The general form is

If(condn 1)

Statement-1;

else if (condn 2)

statement-2;

else if (condn 3)

statement-3;

……….

……….

else if (condn n)

statement-n;

else

default statement;

statement-x;

THE SWITCH STATEMENT

Switch statement is used for complex programs when the number of alternatives

increases. The switch statement tests the value of the given variable against the list of case

values and when a match is found, a block of statements associated with that case is executed.

The general form of switch statement is

switch(expression)

{

case value-1:

block-1

break;

case value-2:

block-2

break;

…….

…….

default:

default-block

break;

}

statement-x;

Eg.::

………

index = marks / 10;

switch(index)

{

case 10:

case 9:

case 8:

grade = “Honours”;

break;

case 7:

case 6:

grade = “first division”;

break;

case 5:

grade = “second division”;

break;

case 4:

grade = “third division”;

break;

default:

grade = “first division”;

break;