External function problem.

2 次查看（过去 30 天）
Chett Manly
Chett Manly 2021-9-18
评论： Chett Manly 2021-9-21
I am trying to alter this code which I have included and is functioning to use an external function.
After a few attempts but always returning errors I am at an end.
I have tried replacing line 8 and 9 with a function look up and recreating the function in the external file but it throws errors.
I believe it is a simple fix but am a bit stuck.
clear; close all; clc
balance(1) = 1000;
contribution = 1200;
M = 1; % month ticker
interest = 0.0025;
while true %this makes the program run until the break condition is met
M = M + 1; % you need to increment months + 1 every cycle
balance(M) = balance(M-1) + interest*balance(M-1) + contribution;
if balance(end) > 500000;
break;
end
end
years = M/12; %year counter
fprintf('%g Months until $500000 reached\n', M);
fprintf('%g Years until $500000 reached\n', years);
format bank
plot(balance);
grid on
ytickformat('usd')
title('Saving 3% compound')
xlabel('Months')
ylabel('Saving balance')
Label = max(balance) %this labels the plot with max balance
txt = {'Max Balance:',Label,'\leftarrow'};
text(M,Label,txt,'HorizontalAlignment','right')
  4 个评论
显示 2更早的评论
Image Analyst
Image Analyst 2021-9-18
Please attach the m-file balance.m -- which I guess is your external function.
Chett Manly
Chett Manly 2021-9-18
This is the code I am trying to make work the same as the original post but this one has to use the function externally.
clear; close all; clc
balance(1) = 1000;
contribution = 1200;
M = 1; % month ticker
interest = 0.0025;
while true %this makes the program run until the break condition is met
M = M + 1; % you need to increment months + 1 every cycle
account(balance, contribution, interest, M)
if balance(end) > 500000;
break;
end
end
years = M/12; %year counter
fprintf('%g Months until $500000 reached\n', M);
fprintf('%g Years until $500000 reached\n', years);
format bank
plot(balance);
grid on
ytickformat('usd')
title('Saving 3% compound')
xlabel('Months')
ylabel('Saving balance')
Label = max(balance) %this labels the plot with max balance
txt = {'Max Balance:',Label,'\leftarrow'};
text(M,Label,txt,'HorizontalAlignment','right')
This is my external function file.
function account(balance, contribution, interest, M);
balance(M) = balance(M-1) + interest*balance(M-1) + contribution;

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2021-9-18
in MATLAB, assigning to one of the input parameters only causes local changes, not change to variable passed in. To change the variable you need to return the new value and assign it to the appropriate location in the calling function.
  3 个评论
显示 1更早的评论
Walter Roberson
Walter Roberson 2021-9-19
clear; close all; clc
balance(1) = 1000;
contribution = 1200;
M = 1; % month ticker
interest = 0.0025;
while true %this makes the program run until the break condition is met
M = M + 1; % you need to increment months + 1 every cycle
balance = account(balance, contribution, interest, M)
if balance(end) > 500000;
break;
end
end
years = M/12; %year counter
fprintf('%g Months until $500000 reached\n', M);
fprintf('%g Years until $500000 reached\n', years);
format bank
plot(balance);
grid on
ytickformat('usd')
title('Saving 3% compound')
xlabel('Months')
ylabel('Saving balance')
Label = max(balance) %this labels the plot with max balance
txt = {'Max Balance:',Label,'\leftarrow'};
text(M,Label,txt,'HorizontalAlignment','right')
function balance = account(balance, contribution, interest, M);
balance(M) = balance(M-1) + interest*balance(M-1) + contribution;
Chett Manly
Chett Manly 2021-9-21
I was so close... Sorry for the late reply, this is exactly it. Thanks!

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Environment and Settings 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by