nested function calculation problem

Hello everyone,

I'm trying to write a code that consists of an if and a nested function. I try, each nested function works seperately but It doesn't work when you put it together. The general structure is as follows. It enters the nested function and calculates correctly, but does not print the answer. Where is the problem?

Thanks

function abc(a1,b1,c1)
x;
y;
z;
    function x
        if statement
            statement
        else  statement
            statement
        end
    end

    function y
        if statement
        else statement
        end
    end

    function z
        if statement
        else statement
        end
    end
result=x+y+z
end

Answer 1

[Walter Roberson]

Your functions do not return values. You cannot add them.

[Cem Eren Aslan]

how can i return values? i try several times, it enter the nested function and it calculate corresponding values but when function end, values disappear.

[Walter Roberson]

With any function, the best approach is most often to just return values. For example,

function result = abc(a1,b1,c1)
x_val = x();
y_val = y();
z_val = z();
    function xv = x()
        if statement
            statement
        else  statement
            statement
        end
        xv = something;
    end

    function yv = y()
        if statement
        else statement
        end
        yv = something;
    end

    function zv = z()
        if statement
        else statement
        end
        zv = something;
    end
result = x_val + y_val + z_val;
end

[Walter Roberson]

But that does not require nested functions (unless the nested functions access shared variables.) There is another opportunity with nested functions:

function result = abc(a1,b1,c1)
x_val = []; y_val = []; z_val = [];   %must initialize, shared variables!
x;
y;
z;
    function x
        if statement
            statement
        else  statement
            statement
        end
        x_val = something;   %no return value, modify shared variable
    end

    function y
        if statement
        else statement
        end
        y_val = something;   %no return value, modify shared variable
    end

    function z
        if statement
        else statement
        end
        z_val = something;   %no return value, modify shared variable
    end

result = x_val + y_val + z_val;  %but you need to return this
end

[Walter Roberson]

Shared variables are slower than passing parameters in and returning outputs.