Matlab has a standard if-elseif-else conditional; for example:
>> t = rand(1); >> if t > 0.75 s = 0; elseif t < 0.25 s = 1; else s = 1-2*(t-0.25); end >> s s = 0 >> t t = 0.7622The logical operators in Matlab are <, >, <=, >=, == (logical equals), and
~=(not equal). These are binary operators which return the values 0 and 1 (for scalar arguments):
>> 5>3 ans = 1 >> 5<3 ans = 0 >> 5==3 ans = 0Thus the general form of the if statement is
if expr1 statements elseif expr2 statements . . . else statements endThe first block of statements following a nonzero expr executes.
Matlab provides two types of loops, a for-loop (comparable to a Fortran do-loop or a C for-loop) and a while-loop. A for-loop repeats the statements in the loop as the loop index takes on the values in a given row vector:
>> for i=[1,2,3,4] disp(i^2) end 1 4 9 16(Note the use of the built-in function disp, which simply displays its argument.) The loop, like an if-block, must be terminated by end. This loop would more commonly be written as
>> for i=1:4 disp(i^2) end 1 4 9 16(recall that 1:4 is the same as [1,2,3,4]).
The while-loop repeats as long as the given expr is true (nonzero):
>> x=1; >> while 1+x > 1 x = x/2; end >> x x = 1.1102e-16