What is the result of this code?

p = 1;
q = 2;
r= 3;
s = 4;
t = r / (~p -q == r - s);

my_func is a function as follows. What is the value of ‘a' at the end of the code below?

function a = my_func(a)
    a = a + 1;
end
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a = 0;
for i = 1:3
    my_func(a);
end
a = my_func(a);