User Input Error? Using input in a function

I am trying to use input to make a functiont that calculates the great circle distance between two sets of coordinates on the surface of the Earth. The problem is I am getting an error on the part that takes input (line 4), long before I get to the calculations. What am I doing wrong?

I've attached the code as well as example coordinates to check it.

[KSSV]

What error you get? What input you tried?

[Olivia Colombo]

It's saying that line 4 is an invalid expression.

[Olivia Colombo]

I tried the first input listed on the attachment.

[Jan]

@Olivia: Please post a copy of the original message. "It's saying ..." sounds cute, but is less useful. Which one is the "line 4"? x = input(prompt)?

Older Matlab version do not accept the double quote to define a string. Which Matlab version are you running?

[Olivia Colombo]

Error using mydistance (line 4)
Error: Invalid expression. Check for missing multiplication operator,
missing or unbalanced delimiters, or other syntax error. To construct
matrices, use brackets instead of parentheses.

[Walter Roberson]

exactly what input are you typing in in response to the prompt ?

[Olivia Colombo]

I've been testing it with: (with and without various degree symbols)

37N, 76W 37N 9W

Answer 1

[Stephan]

Hi,

try:

result = mydistance

function d = mydistance
    prompt = 'Input coordinates between which you want to find the great circle distance (XºN, XºW XºN, XºW): \n';
    getridof = ["N","W",",",char(176)];
    x = input(prompt,'s');
    x = double(string(split(replace(x,getridof,""))));
    a = acos(sin(deg2rad(x(1)))*sin(deg2rad(x(3)))+cos(deg2rad(x(1)))*cos(deg2rad(x(3)))*cos(abs(deg2rad(x(2)))-deg2rad(x(4))));
    d = a*.6371;
    disp(['The great circle distance in km is: ',num2str(d)])
end

for input:

Input coordinates between which you want to find the great circle distance (XºN, XºW XºN, XºW): 
37°N, 76°W 37°N, 9°W

the result is:

The great circle distance in km is: 0.58165

result =

    0.5817

Best regards

Stephan