Conditional Statements
When ever you want to perform a set of operations based on a condition(s) If / If-Else / Nested ifs are used.
You can also use if-else , nested IFs and IF-ELSE-IF ladder when multiple conditions are to be performed on a single variable.
1. If
Syntax
if(conditional-expression)
{
//code
}
Example
int x = 30;
int y = 30;
if ( x == y) {
println "x and y are equal";
}
Check result here
2. If-else
Syntax
if(conditional-expression)
{
//code
} else {
//code
}
Example
int x = 30;
int y = 20;
if ( x == y) {
println "x and y are equal";
} else {
println "x and y are not equal";
}
Check result here
3. If-else-if ladder
Syntax
if(conditional-expression-1)
{
//code
} else if(conditional-expression-2) {
//code
} else if(conditional-expression-3) {
//code
}
....
else {
//code
}
Example
int age = 15;
if ( age <= 1 && age >= 0) {
println "Infant";
} else if (age > 1 && age <= 3) {
println "Toddler";
} else if (age > 3 && age <= 9) {
println "Child";
} else if (age > 9 && age <= 18) {
println "Teen";
} else if (age > 18) {
println "Adult";
} else {
println "Invalid Age";
}
Check result here
4. Nested-If
Nested-Ifs represents if block within another if block.
Syntax
if(conditional-expression-1) {
//code
if(conditional-expression-2) {
//code
if(conditional-expression-3) {
//code
}
}
}
Example
int age = 50;
char resident = 'Y';
if (age > 18)
{
if(resident == 'Y'){
println "Eligible to Vote";
}
}
Check result here
5. Switch
Switch is an alternative to IF-ELSE-IF ladder and to select one among many blocks of code.
Syntax
switch(conditional-expression){
case value1:
// code
break; //optional
case value2:
// code
break; //optional
...
default:
//code to be executed when all the above cases are not matched;
}
Example
int day = 3;
switch(day){
case 1: println "Sunday";
break;
case 2: println "Monday";
break;
case 3: println "Tuesday";
break;
case 4: println "Wednesday";
break;
case 5: println "Thursday";
break;
case 6: println "Friday";
break;
case 7: println "Saturday";
break;
default:println "Invalid day";
break;
}