c - assigning a 2D array element to single pointer -


i trying learn c. new c programming. have following function.

/*da pointer 2d array*/     void normalizecols(float* dmu, float* dsigma, float* db, float* da, int n){        int col, row;        for(col=0; col < n; col++)            /*step 1: calculating mean*/             float tempmu = 0.0;              dmu = &tempmu;             (row=0; row < n; row++){                 /*i adding elements of column*/                 dmu += *(*(da+row)+col); //error: operand of * must pointer             }             /*dividing dmu number of dimension(square matrix)*/                           dmu /= (float) n; //error: expression must have arithmetic or enum type             //more code here        } }

i trying find mean of column. 2 errors have commented in above snippet. how should fix this?

if know matrices square (i.e. row-length n number of rows), addressing manually.

the inner loop becomes:

       /*step 1: calculating mean*/        float tempmu = 0;        (row=0; row < n; row++){            /*i adding elements of column*/            tempmu += da[col * n + row];        }        /*dividing dmu number of dimension(square matrix)*/                      tempmu /= (float) n;

also, make input arguments const make clearer, , switch int size_t.

of course, make sure accesses in proper order (either row-major or column-major) otherwise you'll horrible cache thrashing.


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