langref.org - java - Structure

Perform an action if a condition is true (IF .. THEN)

Given a variable name, if the value is "Bob", display the string "Hello, Bob!". Perform no action if the name is not equal.

java

if (name.equals("Bob")) {
System.out.println("Hello, Bob!");
}

Perform different actions depending on a boolean condition (IF .. THEN .. ELSE)

Given a variable age, if the value is greater than 42 display "You are old", otherwise display "You are young"

java

if (age > 42) {
System.out.println("You are old");
} else {
System.out.println("You are young");
}

System.out.println("You are " + ((age>42)?"old":"young"));

Perform different actions depending on several boolean conditions (IF .. THEN .. ELSIF .. ELSE)

java

if (age > 84) System.out.println("You are really ancient");
else if (age > 30) System.out.println("You are middle-aged");
else System.out.println("You are young");

Replacing a conditional with many branches with a switch/case statement

Many languages support more compact forms of branching than just if ... then ... else such as switch or case or match. Use such a form to add an appropriate placing suffix to the numbers 1..40, e.g. 1st, 2nd, 3rd, 4th, ..., 11th, 12th, ... 39th, 40th

java

String[] array = new String[40];
for(int n = 1; n <= array.length; n++)
array[n-1] = Integer.toString(n);
for(int n = 0; n < array.length; n++)
{
int y = Integer.parseInt(array[n]);
if(array[n].length() > 1)
y = Integer.parseInt(array[n].substring(1));
switch(y)
{
case 1: {array[n] += "st"; break;}
case 2: {array[n] += "nd"; break;}
case 3: {array[n] += "rd"; break;}
default: array[n] += "th";
}
}