% Function Name: ugaMath % Inputs (1): - (char) A string containing numbers and

Question

% Function Name: ugaMath
% Inputs (1): - (char) A string containing numbers and mathematical
%                operators.
% Outputs (1): - (double) A number after performing the arithmetic
%
% Function Description:
%   Write a function named "ugaMath" that takes in a string containing a
%   arithemtic expression and returns the result as a type double from
%   carrying out all indicated mathematical operations. The input will
%   follow this format:
%  
%   '<number><operator><number><operator><number>' and so on inside the
%   string.
%
%   <number> is replaced by a number, and <operator> is replaced by one of
%   these five arithmetic operators: +, -, *, /, or ^. Since UGA ignores
%   (or to be precise, forgets) the order of operations, the function
%   should do the same.
%
%   For example, the following expression is a problem stolen from UGA's
%   MATH 4102 final exam. Supposed we have the string '5-2^3'. 5-2 would
%   give 3, so 3^3 would give 27 as the final answer for the output.
%
% Notes:
%   - The input string is guaranteed to start with a number. If the input
%     contains only one number and nothing else, the function should return
%     that number.
%   - You may assume that the string does not contain negative numbers as
%     operands, though the output may be negative.
%   - The input would not contain an operator with no operands after it
%     e.g. you will not be given '80+' as an input. Furthermore, the input
%     would not contain any characters other than numbers and the five
%     aforementioned operators.
%
% Hints:
%   - The strtok() function may be useful.
%   - While str2num() may seem like an easy solution, it will not give the
%     correct answer for every case.
%
% Test Cases:
%   num1 = ugaMath('20-35')
%       num1 => -15
%
%   num2 = ugaMath('11*37/82+3')
%       num2 => 7.9634
%
%   num3 = ugaMath('9.4')
%       num3 => 9.4
%
%   num4 = ugaMath('235^0/0.32*5.55-103.2+589.32/23.6^2.32*0.045+32-218')
%       num4 => -131.4716

Explanation / Answer

function y = ugaMath(s)

s = regexprep(s,'[0-9]*.?[0-9]+',' $0 ');

v = regexp(s,' ','split');

l=length(v);

res=eval(v{2});

i=2;

while(i < (l-1) )

res=eval(strcat(num2str(res),v{i+1},v{i+2}));

i=i+2;

end

y=res;

end

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