Decision Making
Decision making comes with if else and switch statement.
if:
If statement, is a statement, a particular condition is checked either true or false.
We can do any statement execution in either true or false conditions. If the statement is true ,
we can execute some statement, if false we can also execute any statement.The Decision
making of if statement, not only over a particular variable or calculation, +,-, * and operator
like ||, && can be applied during the checking. System define function like
Sum,Add from System. Mathematics can be appear during the checking.
User defined function also can be applied during the checking of if condition. When we are
checking ,the condition is true or false, the statement are not check partially , as a whole it
should be checked either true or false. Here is the example of if statement.
Syntax:
if (boolean check)
{
/* execute statement
}
int
age = 20;
if
(age > 18)
Console.WriteLine("Hey!
You are eligible for credit card!");
if else statement
If else also a branching, to have both statement .In if condition , there should be some
statement , in if part and some statement else part. If else condition, can have
multiple branches. In if else, we can write else if to check further condition and do
branching.If else statement can be nested, that means write one if else statement under
another If else statement. Below is the example of nested if else.
Syntax:
if(boolean check)
{
/* execute statement
}
else
{
/* execute statement
}
if(boolean check)
{
/* execute statement
}
else
{
/* execute statement
}
Example 1
int age = 20;
int height = 20;
int age = 20;
int height = 20;
if
((age > 10) || (height < 6))
Console.WriteLine("Hey!
You are eligible for Vollyball!");
else
Console.WriteLine("Better
Next Tiem!");
Example 2
int
age = 20;
int
height = 20;
if
((age <= 10) && (height >= 4))
Console.WriteLine("You
are eligble for participate in sports!");
else
Console.WriteLine("Hey!
Sorry Next Time!");
Nested if statements
Syntax:
if(boolean check)
if(boolean check)
{
/* execute statement
}
else if( next boolean check)
{
/* execute statement
}
else
{
/* execute statement
}
Example 1
if
(age > 18)
Console.WriteLine("Hey!
Your age suitable for Participate!");
else
if
(height < 5)
Console.WriteLine("Hey!
Your height not suitable for Participation !");
else
Console.WriteLine("Yes
! Both you age and heigh permit for Participation !");
Switch Statement
The switch statement is multiple branching statement, depending upon the condition , the
control is transferred to the many possible points. For example I have written i=5.
The switch statement content,i=0, one condition,i=1, another condition, i=2, another
condition and so on. When we write switch statement, the control will go directly to the i=5.
The switch statement consists of break statement, break statement works when the
condition satisfied. Default is an optional part of switch statement, which says that,
when no condition satisfied, the control will go to default. Switch statement can be nested,
that means a switch statement can be written to another switch statement.The innermost
will break first and the immediate parent statement will be break next . Here is the
example of switch statement and nested switch statement.
Example 1
int
age = 4;
switch
(age)
{
case
0:
Console.WriteLine("Your
age is less than zero");
break;
case
1:
Console.WriteLine("Your
age is one");
break;
case
2:
Console.WriteLine("Your
age is two");
break;
case
3:
Console.WriteLine("Your
age is three");
break;
case
4:
Console.WriteLine("Your
age is four");
break;
}
Example 2
int
age = 1000;
switch
(age)
{
case
0:
Console.WriteLine("Your
age is less than zero");
break;
case
1:
Console.WriteLine("Your
age is one");
break;
case
2:
Console.WriteLine("Your
age is two");
break;
case
3:
Console.WriteLine("Your
age is three");
break;
case
4:
Console.WriteLine("Your
age is four");
break;
default:
Console.WriteLine("I'm
sorry, I don't understand that!");
break;
}
Nested Switch Statements
Example 1
char
i = 'l';
switch
(i)
{
case
'i':
case
'j':
switch
(i)
{
case
'k':
case
'l':
return
true;
}
break;
}
The ? : Operator
Ternary operator , can be applied like if else. Here a condition is written fast, question mark
is put, condition written, the first expression is written, is the second expression is written.
It works as a simple if else statement in a smart way. Here is the example of ternary operator.
The ternary operator can be nested type also, another Ternary operator can be written within
a ternary operator. The whole act as a simple statement of if else and return the results. Here is the
example of nested ternary operator. This example so, how a and b initialize and check
which is greater.
condition ? first_expression : second_expression;
//
if-else construction.
if
(i > 0)
l
= "true";
else
l
= "false";
Example 1
Example 1
//
?: conditional operator.
l
= (i > 0) ? "true"
: "true";
Example 2
Goto : Go to statement, is a piece of program which moves the control of program to a
particular part of the program.Go to statement, followed by level name tells the program
to go the particular level statement. Goto can be applied
Here are some example of go to statement. Example shows that.
How control moves to another program level.
This example shows that how a for loop can be break by go to statement. When a particular
condition is reached, the go to statement moves the control of program form a for loop to a
particular level.
Below is example of switch statement. When a particular case match , go to statement fires to
move controller from another.
int
a = 2;
int
b = 5;
string
r = a > b ? "a
is greater than b"
: b > a ? "b
is greater than a"
: "not
sure";
Goto : Go to statement, is a piece of program which moves the control of program to a
particular part of the program.Go to statement, followed by level name tells the program
to go the particular level statement. Goto can be applied
- loop
- switch statement
- multi level loop multi level switch statement
- program statement
Here are some example of go to statement. Example shows that.
How control moves to another program level.
protected
void
Page_Load(object
sender, EventArgs
e)
{
int
age = 21;
if
(age < 18)
{
Console.Write("You
are not agibible for credit card");
}
else
if
(age >18)
{
goto
credit_card_process;
}
else
if
(age == 18)
{
Console.Write("we
are checking your eligiblity");
}
credit_card_process:
card_process();
}
public
void
card_process()
{
//statement
ommitted
}
This example shows that how a for loop can be break by go to statement. When a particular
condition is reached, the go to statement moves the control of program form a for loop to a
particular level.
protected
void
Page_Load(object
sender, EventArgs
e)
{
for
(int
i = 0; i < 50; i++)
{
if
(i == 25)
{
goto
final;
}
}
final:
Console.WriteLine("you
number 25 has found , no need to furthher loop");
}
Below is example of switch statement. When a particular case match , go to statement fires to
move controller from another.
switch
(i)
{
case
1:
stardrad="Student
of Class One";
break;
case
2:
stardrad="Student
of Class two";
break;
case
3:
stardrad="Student
of Class tree";
break;
case
4:
stardrad="Student
of Class four";
break;
case
10:
goto
case
1;
}
