Question

I’m running this code to calculate square root of x[i][j] - y[j] but it gives me nonsense!

     bool X[I][J]={};   //nodes
     bool Y[J]={};      //medians

    double denominator=0;
    double miu=0;
    outFile<< "denominator= " << denominator << endl;
    for(i=0;i<I;i++)
        for(j=0;j<J;j++)
        {
            denominator+=sqrt(double (X[i][j]-Y[j]));
        }
    outFile<< "denominator= " << denominator << endl;

The first outFile prints 0 which is the original value but the second one prints -1.#IND.

Answer 1

That probably means that at some point X[i][j] - Y[j] was negative, and you’re getting a NaN (not a number) back from sqrt.

See this wikipedia page for an explanation of NaNs.

Also, X and Y are arrays of booleans, so X[i][j] - Y[j] will always be 1, 0, or -1, and you really don’t need the sqrt. Is this what you want?