statements ‘if’, ‘for’, ‘while’, and ‘repeat-until’

if, for, while and repeat-until

The syntax of the ‘if’ and ‘while’ statements are shown in this example:

if n%2 == 0 { 

  s = "even" 

} 

else { // the else part is optional 

  s = "odd" 

} 

var i = 0; 


while i < 5 {

  Out println: i; 

  ++i

}
 

Note that ( ) as not necessary for the ‘if’ and ‘while’ expressions but the { } are mandatory.

Be aware that indentation must be respected when using these statements. See the Cyan manual for rules regarding the if statement. In particular, the } that closes a while statement should be either in the same line as keyword while or in the same column as it. There should be no semicolon after any } symbol.

There is a repeat-until statement that executes its statements until the until expression evaluates to true

repeat 

  sum = sum + n; 

  ++n; 

until n >= 4; 

For statement for can be used to iterate over any object that implements method iterator -> Iterator<T>. Arrays and intervals implement it:

for elem in [ 2, 3, 5, 7 ] { 

  "$elem is prime" println 

} 

var s = 0;

for n in 1..100 { 

  s = s + n 

} 

assert s == 5050;