how to write this c++ code in matlab form

for(i=0;i<=80;i++) {
 wv[i]=380+i*5;
}

double findpeak( double* wv, double x[][50]) // find the peak of a spectrum
{ double temp=x[0][0];
  int index=0;
  for(int i=1;i<=80;i++)
  { if (x[i][0]>temp)
    { temp=x[i][0];index=i;};
  }
  return wv[index];
};

[Walter Roberson]

That is not valid c++ code. You allocate x as a 2d array with 0 rows and 0 columns and no particular initial value. This local variable hides the x passed in as an parameter. You then attempt to access the second through eighty first columns of the empty x and you expect that array overrun to work and to have initialized values.

[Stephen23]

Original question: https://webcache.googleusercontent.com/search?q=cache:bEd5R1Q0FYIJ:https://www.mathworks.com/matlabcentral/answers/418423-how-to-write-this-c-code-in-matlab-form

for(i=0;i<=80;i++) { wv[i]=380+i*5; } double findpeak( double* wv, double x[][50]) // find the peak of a spectrum { double temp=x[0][0]; int index=0; for(int i=1;i<=80;i++) { if (x[i][0]>temp) {temp=x[i][0];index=i;}; } return wv[index]; };

Answer 1

[Walter Roberson]

The equivalent MATLAB code would be

error('Subscript out of range') ;

[John D'Errico]

:)

[James Tursa]

Or

exit

Answer 2

[Guillaume]

is it correct

Certainly not! It doesn't look like you know what the zeros function does.

x = zeros(0,0);

is exactly the same as

x = [];

and creates an empty matrix. zeros(j, 0) creates a matrix with j rows and 0 columns, another kind of empty matrix. Why would you want to compare that to another empty matrix?

how to write this c++ code in matlab form

Matlab is not C++ and trying to translate C++ code into matlab line by line would be a complete waste of time. C++ is a low level language where you have to write all the operations yourself. In matlab, you can use higher level function that do the work for you. Case in point, that C++ findpeak function would be just two lines in matlab:

function peak = findpeak(wv, x)
   [~, idx] = max(x(:, 1));
   peak = wv(idx);
end