Class 39: Stack lab

Held Wednesday, April 14

Summary

• RPN calculation
• dc
• Lab: Stacks

Contents

Handouts

• Project guidelines (draft)
• Project teams
• Stacks

Notes

• assignment 8 is due.
• Reminder: We may have prospective students visiting on Friday. Be here and be positive.

An RPN calculator

• Almost every Unix platform comes with an RPN calculator called dc.
• Basics:
  • To print the top of the stack, use p.
  • To add a number, just type it.
  • To execute an operation, just type it.
• We'll spend a little time playing with dc.

  % dc
  3 4 + p
  7
  2 / p
  3
  

• Exit with control-D.
• By default, dc rounds before the decimal point. You can also set it to N places of precision after the decimal point with the k operator.

  % dc
  1 3 / p
  
  2 k p
  
  1 3 / p
  .33
  10 k
  1 3 / p
  .3333333333
  

• Read the man page.

  % man dc
  

• What operations does dc support?
• What's the largest number dc can compute?
  • How might you determine this experimentally?

Lab

Do the undetailed stacks lab.

History

• Created Monday, January 11, 1999.
• Added short summary on Friday, January 22, 1999.
• On Wednesday, April 14, 1999, filled in some details.