Skip to main content

4 - Functions and Program Structure

Exercise 4-1​

Write the function strrindex(s, t), which returns the position of the rightmost occurrence of t in s, or -1 if there is none. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-2​

Extend atof to handle scientific notation of the form

123.45e-6

where a floating-point number may be followed by e or E and an optionally signed exponent. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-3​

Given the basic framework, it's straightforward to extend the calculator. Add the modulus (%) operator and provisions for negative numbers. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-4​

Add commands to print the top element of the stack without popping, to duplicate it, and to swap the top two elements. Add a command to clear the stack. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-5​

Add access to library functions like sin, exp, and pow. See <math.h> in Appendix B, Section 4. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-6​

Add commands for handling variables. (It's easy to provide twenty-six variables with single-letter names.) Add a variable for the most recently printed value. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-7​

Write a routine ungets(s) that will push back an entire string onto the input. Should ungets know about buf and bufp, or should it just use ungetch? [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-8​

Suppose that there will never be more than one character of pushback. Modify getch and ungetch accordingly. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-9​

Our getch and ungetch do not handle a pushed-back EOF correctly. Decide what their properties ought to be if an EOF is pushed back, then implement your design. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-10​

An alternate organization uses getline to read an entire input line; this makes getch and ungetch unnecessary. Revise the calculator to use this approach. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-11​

Modify getop so that it doesn't need to use ungetch. Hint: use an internal static variable. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-12​

Adapt the ideas of printd to write a recursive version of itoa; that is, convert an integer into a string by calling a recursive routine. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-13​

Write a recursive version of the function reverse(s), which reverses the string s in place. [1]

My solution​

tbd

Official solution​

tbd

Exercise 4-14​

Define a macro swap(t, x, y) that interchanges two arguments of type t. (Block structure will help.) [1]

My solution​

tbd

Official solution​

tbd