Why is my function not working?

%clear program all together
clear
clc

%create function for velocity(m/s)
function U = (n,S,H,B);
U = sqrt(S)*((B*H/(B+2*H))^(2/3))/n;

T = zeros(6,5);
for i = (1:5)
T(2,1)=0.036;T(2,2)=0.0001;T(2,3)=10;T(2,4)=2;T(2,5)=velocity(.036,.0001,10,2);
T(3,1)=0.020;T(3,2)=0.0002;T(3,3)=8;T(3,4)=1;T(3,5)=velocity(.020,.0002,8,1);
T(4,1)=0.015;T(4,2)=0.0012;T(4,3)=20;T(4,4)=1.5;T(4,5)=velocity(.015,.0012,20,1.5);
T(5,1)=0.030;T(5,2)=0.0007;T(5,3)=25;T(5,4)=3;T(5,5)=velocity(.030,.0007,25,3);
T(6,1)=0.022;T(6,2)=0.0003;T(6,3)=15;T(6,4)=2.6;T(6,5)=velocity(.022,.0003,15,2.6);
end

Answer 1

[Yongjian Feng]

You meant:

function U = velocity(n,S,H,B)
    U = sqrt(S)*((B*H/(B+2*H))^(2/3))/n;
end

[Eric Hofmann]

it won't accept the 'end' after the function

[Yongjian Feng]

Save your function into a velocity.m file, and run the test from matlab command line window.

1. Your velocity.m has the function:

function U = velocity(n,S,H,B)
    U = sqrt(S)*((B*H/(B+2*H))^(2/3))/n;
end

2. Then run the test from the command line window.

T = zeros(6,5);
for i = (1:5)
    T(2,1)=0.036;T(2,2)=0.0001;T(2,3)=10;T(2,4)=2;T(2,5)=velocity(.036,.0001,10,2);
    T(3,1)=0.020;T(3,2)=0.0002;T(3,3)=8;T(3,4)=1;T(3,5)=velocity(.020,.0002,8,1);
    T(4,1)=0.015;T(4,2)=0.0012;T(4,3)=20;T(4,4)=1.5;T(4,5)=velocity(.015,.0012,20,1.5);
    T(5,1)=0.030;T(5,2)=0.0007;T(5,3)=25;T(5,4)=3;T(5,5)=velocity(.030,.0007,25,3);
    T(6,1)=0.022;T(6,2)=0.0003;T(6,3)=15;T(6,4)=2.6;T(6,5)=velocity(.022,.0003,15,2.6);
end
T

Answer 2

[per isakson]

The function must be at the end of the m-file. It's a local file in a script. (Or you can have the script and the function in two separate files. See Scripts vs. Functions.)

%%
T = zeros(6,5);
for i = (1:5)
    T(2,1)=0.036;T(2,2)=0.0001;T(2,3)=10;T(2,4)=2;T(2,5)=velocity(.036,.0001,10,2);
    T(3,1)=0.020;T(3,2)=0.0002;T(3,3)=8;T(3,4)=1;T(3,5)=velocity(.020,.0002,8,1);
    T(4,1)=0.015;T(4,2)=0.0012;T(4,3)=20;T(4,4)=1.5;T(4,5)=velocity(.015,.0012,20,1.5);
    T(5,1)=0.030;T(5,2)=0.0007;T(5,3)=25;T(5,4)=3;T(5,5)=velocity(.030,.0007,25,3);
    T(6,1)=0.022;T(6,2)=0.0003;T(6,3)=15;T(6,4)=2.6;T(6,5)=velocity(.022,.0003,15,2.6);
end
disp(T)

         0         0         0         0         0
    0.0360    0.0001   10.0000    2.0000    0.2607
    0.0200    0.0002    8.0000    1.0000    0.4278
    0.0150    0.0012   20.0000    1.5000    1.8602
    0.0300    0.0007   25.0000    3.0000    1.1116
    0.0220    0.0003   15.0000    2.6000    0.8872

%% create function for velocity(m/s)
function U = velocity(n,S,H,B);
    U = sqrt(S)*((B*H/(B+2*H))^(2/3))/n;
end

Answer 3

[Image Analyst]

Try this:

% Demo by Image Analyst
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 25;
fprintf('Beginning to run %s.m ...\n', mfilename);

% Call the function
U = velocity(4,37,73,42);
fprintf('Done running %s.m\n', mfilename);

T = zeros(6,5);
for i = (1:5)
	T(2,1)=0.036;
	T(2,2)=0.0001;
	T(2,3)=10;
	T(2,4)=2;
	T(2,5)=velocity(.036,.0001,10,2);
	T(3,1)=0.020;
	T(3,2)=0.0002;
	T(3,3)=8;
	T(3,4)=1;
	T(3,5)=velocity(.020,.0002,8,1);
	T(4,1)=0.015;
	T(4,2)=0.0012;
	T(4,3)=20;
	T(4,4)=1.5;
	T(4,5)=velocity(.015,.0012,20,1.5);
	T(5,1)=0.030;
	T(5,2)=0.0007;
	T(5,3)=25;
	T(5,4)=3;
	T(5,5)=velocity(.030,.0007,25,3);
	T(6,1)=0.022;
	T(6,2)=0.0003;
	T(6,3)=15;
	T(6,4)=2.6;
	T(6,5)=velocity(.022,.0003,15,2.6);
end

% Create function for velocity(m/s)
function U = velocity(n,S,H,B)
U = sqrt(S)*((B*H/(B+2*H))^(2/3))/n;
end