think2times

摘要： Exercise 2.10 Ben Bitdiddle, an expert systems programmer, looks over Alyssa’s shoulder and comments that it is not clear what it means to divide by a 阅读全文

摘要： Exercise 2.11 In passing, Ben also cryptically comments: “By testing the signs of the endpoints of the intervals, it is possible to break mul-interval 阅读全文

摘要： Exercise 2.9 The width of an interval is half of the difference between its upper and lower bounds. The width is a measure of the uncertainty of the n 阅读全文

摘要： Exercise 2.8 ＞ Using reasoning analogous to Alyssa's, describe how the difference of two intervals may be computed. Define a corresponding subtraction 阅读全文

摘要： 2.7 Alyssa’s program is incomplete because she has not specified the implementation of the interval abstraction. Here is a definition of the interval 阅读全文

摘要： Exercise2.6 In case representing pairs as procedures wasn't mind-boggling enough, consider that, in a language that can manipulate procedures, we can 阅读全文

摘要： Exercise 2.5 Show that we can represent pairs of nonnegative integers using only numbers and arithmetic operations if we represent the pair a and b as 阅读全文

摘要： Exercise 2.4 Here is an alternative procedural representation of pairs. Forthisrepresentation, verify that (car (cons x y)) yields x for any objects x 阅读全文

摘要： Exercise 2.3 Implement a representation for rectangles in a plane. (Hint: You may want to make use of Exercise 2.2.) In terms of your constructors and 阅读全文

摘要： Exercise 2.2 Consider the problem of representing line segments in a plane. Each segment is represented as a pair of points: a starting point and an e 阅读全文