private int readCommand (boolean charstring) {
        while (true) {
            int t = readNext (charstring);
            if (t == CMD) {
                /*
                System.out.print("CMD= "+num+", args=");
                for (int i=0; i<stackptr; i++) {
                System.out.print(" "+stack[i]);
                }
                System.out.println();
                 */
                return num;
            } else {
                stack[stackptr++] = (t == NUM) ? (float) num : fnum;
            }
        }
    }