コード例 #1
0
 public void appendOutputString(ExpressionProgram prog, int myIndex, StringBuffer buffer) {
   // The ExpressionCommand occurs in the program prog at the index indicated by myIndex.
   // Add a print string representation of the sub-expression represented by this command
   // (including any previous commands in the program that generate data used by this
   // command).
   int upper = prog.extent(myIndex - 1);
   buffer.append("sum(");
   buffer.append(sumVar.getName());
   buffer.append(", ");
   prog.appendOutputString(myIndex - 1 - upper, buffer);
   buffer.append(", ");
   prog.appendOutputString(myIndex - 1, buffer);
   buffer.append(", ");
   buffer.append(sumExpr.toString());
   buffer.append(")");
 }
コード例 #2
0
 public void apply(StackOfDouble stack, Cases cases) {
   // This routine is called when an ExpressionCommand object is encountered during
   // the evaluation of an ExpressionProgram.  The stack may contain results of
   // previous commands in the program.  In this case, the command is a summation
   // and the stack contains the upper and lower limits summation limits.
   double upper = Math.round(stack.pop()) + 0.1; // Get summation limits.
   double lower = Math.round(stack.pop());
   if (Double.isNaN(upper) && Double.isNaN(lower) || upper - lower > 1000000)
     stack.push(Double.NaN);
   double sum = 0;
   for (double x = lower; x <= upper; x++) { // Compute the sum.
     sumVar.setVal(x);
     sum += sumExpr.getVal();
   }
   stack.push(sum); // Leave the sum on the stack.
 }