Global variables in functions

Question

farheen asdf 2017-9-11

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/356111-global-variables-in-functions

评论： Image Analyst 2019-10-7

I have been trying to use global variables so I can make changes to the said variable in different functions but I can't seem to do it. It seems like the second function does not work. Please help.

    function one=new1()
clc
clear global
global m
m=0;
disp('soup')
function hamburger=eat()
m=m+1
disp('sandwich')

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2017-9-11

3
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/356111-global-variables-in-functions#answer_281106

编辑：Image Analyst 2017-9-11

在 MATLAB Online 中打开

Get rid of the "clear global" function in new1(), which blew away your existing globals, and add "global m" to eat():

function one=new1()
global m
clc
m=0;
disp('soup')
function hamburger=eat()
global m
m=m+1
disp('sandwich')

And the variables are only global for the functions that actually have the "global m" line in them, not to other functions that don't have that line.

See the FAQ on globals: http://matlab.wikia.com/wiki/FAQ#Are_global_variables_bad.3F

3 个评论
显示 1更早的评论隐藏 1更早的评论

farheen asdf 2017-9-11

The second function is still not working. I know this because the disp('sandwich') command is not working and the value of m is not increasing either

Image Analyst 2017-9-11

It must not be getting called. Set a breakpoint inside eat() and start your program. See if it stops there. It probably doesn't which means that eat() never gets called. Step through your program from earlier to see what lines of code get executed and try to figure out where you're calling it and why program execution never reaches that line of code.

请先登录，再进行评论。

Answer 2

dpb 2017-9-11

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/356111-global-variables-in-functions#answer_281105

在 MATLAB Online 中打开

>> help clear
   ...
 | clear GLOBAL removes all global variables.
   ...

However, using global is not recommended as a general programming practice; you don't show enough context to see why there's any reason should be using one here so I'd suggest not doing so.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 3

Raja Awais Liaqait 2019-10-7

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/356111-global-variables-in-functions#answer_395133

I want help in the following code.

global min_realvar ;

global max_realvar ;

Firstly, I want to get the value of these variables and secondly i want to write them in such away that I can give the values of these variables as an input.

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Image Analyst 2019-10-7

在 MATLAB Online 中打开

You already HAVE them since you put the global line in your workspace. No need to do anything more. Get them into another variable by referencing them.

someOtherVariable = min_realvar * 500 + 123424; % Whatever....

If you want, you can just pass them in as variables in the input argument list. Or you can write them to a disk file and pass the filename.

请先登录，再进行评论。