rules below are in matlab

main.m
if condition
    % code to execute if condition is true
else
    % code to execute if condition is false
end
109 chars
6 lines

main.m
x = 10;

if x > 0
    disp('x is positive');
else
    disp('x is non-positive');
end
85 chars
8 lines

main.m
x is positive
14 chars
2 lines

main.m
switch variable
    case value1
        % code to execute if variable is equal to value1
    case value2
        % code to execute if variable is equal to value2
    otherwise
        % code to execute if variable does not match any case
end
242 chars
9 lines

main.m
day = 'Monday';

switch day
    case 'Monday'
        disp('Start of the week');
    case 'Friday'
        disp('End of the week');
    otherwise
        disp('Some other day');
end
182 chars
11 lines

main.m
Start of the week
18 chars
2 lines