1. Simple if:
The syntax is given below if(expression)
statement;
or
if(expression)
{
Block of statements
}
First expression evaluates if it is true then only statement will be executed.
eg: if (n>0)
cout<<n<<"is positive";
2. if else:
The syntax is given below, if (expression)
statement 1;
else
statement 2;
or
if (expression)
{
statement block 1;
}
else
{
statement block 2;
}
First expression evaluates if it is true statement block 1 will be executed otherwise statement block 2 will be executed. Only one block will be executed at a time so it is called branching statement.
eg:
if (n>0)
cout<<n<<"is positive";
else
cout<<n<<"is negative";
3. if else if ladder:
The syntax will be given below
if (expression!)
{
statement block 1;
}
else if (expression 2)
{
statement block 2;
}
else if (expression 3)
{
statement block 3;
}
else
{
statement block n;
}
Here first expression 1 will be evaluated if it is true only the statement blockl will be executed otherwise expression 2 will be executed if it is true only the statement block 2 will be executed and so on. If all the expression evaluated is false then only statement block n will be evaluated .
eg:
If (mark>=90)
cout<<"Your grade is A+";
else if(mark>=80)
cout<<"Your grade is A";
else if(mark>=70)
cout<<"Your grade is B+";
else if(mark>=60)
cout<<"Your grade is B";
else if(mark>=50)
cout<<"Your grade is C+";
else if(mark>=40)
cout<<"Your grade is C";
else if(mark>=30)
cout<<"Your grade is D+";
else
cout<<"Your grade is D";
4. conditional operator:
It is a ternary operator and it is an alternative for if else construct.
The syntax is given below.
expression 1? expression 2: expression 3;
or
expression 1? Value if true : value if false;
Here
expression 1 will be evaluated if it true
expression 2 will be executed otherwise
expression 3 will be executed.
eg:
n>0?cout<<n<<"is positive":cout<<n<<"is negative";
5. Switch:
It is a multiple branch statement. Its syntax is given below.
switch(expression)
{
case value: statements;break;
case value: statements;break;
case value: statements;break;
case value: statements;break;
case value: statements;break;
……..
default : statements;
}
First expression evaluated and selects the statements with matched case value.
eg:
switch (n)
{
case 1: cout<< “Sunday”;break;
case 2: cout<< “Monday”;break;
case 3: cout<< “Tuesday”;break;
case 4: cout<< “Wedesday”;break;
case 5: cout<< “Thursday”;break;
case 6: cout<< “Friday”;break;
case 7: cout<< “Saturday”;break;
default : cout<< “lnvalid”
}
