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Answer to Exercise 2-10, page 52 Solution by Bryan Williams Rewrite the function lower, which converts upper case letters to lower case, with a conditional expression instead of if-else . /* Exercise 2-10. Rewrite the function lower, which converts upper case letters to lower case, with a conditional expression instead of if-else. Assumptions : by conditional expression they mean an expression i..

Answer to Exercise 2-9, page 51 Solution by Gregory Pietsch In a two's complement number system, x &= (x-1) deletes the rightmost 1-bit in x . Explain why. Use this observation to write a faster version of bitcount . bitcount is written on p.50 as this: /* bitcount: count 1 bits in x */ int bitcount(unsigned x) { int b; for (b = 0; x != 0; x >>= 1) if (x & 01) b++; return b; } Answer: If x is od..

Answer to Exercise 2-8, page 49 Solutions by Gregory Pietsch and Bob Wightman Write a function rightrot(x,n) that returns the value of the integer x rotated to the right by n bit positions. Greg's Cat 0 solution unsigned rightrot(unsigned x, unsigned n) { while (n > 0) { if ((x & 1) == 1) x = (x >> 1) | ~(~0U >> 1); else x = (x >> 1); n--; } return x; } /* main driver added, in a hurry while tir..

Answer to Exercise 2-7, page 49 Solution by Gregory Pietsch Write a function invert(x,p,n) that returns x with the n bits that begin at position p inverted (i.e., 1 changed into 0 and vice versa), leaving the others unchanged. unsigned invert(unsigned x, int p, int n) { return x ^ (~(~0U

Answer to Exercise 2-6, page 49 Solution by Richard Heathfield Write a function setbits(x,p,n,y) that returns x with the n bits that begin at position p set to the rightmost n bits of y, leaving the other bits unchanged. This one's scary. #include unsigned setbits(unsigned x, int p, int n, unsigned y) { return (x & ((~0

Answer to Exercise 2-5, page 48 Solution 1 by Richard Heathfield Solution 2 by Partha Seetala Write the function any(s1,s2) , which returns the first location in the string s1 where any character from the string s2 occurs, or -1 if s1 contains no characters from s2 . (The standard library function strpbrk does the same job but returns a pointer to the location.) Here is my solution, which is ver..

Answer to Exercise 2-4, page 48 Solution by Richard Heathfield Write an alternate version of squeeze(s1,s2) that deletes each character in the string s1 that matches any character in the string s2 . /* * Exercise 2-4 Page 48 * * Write an alternate version of squeeze(s1,s2) that deletes each * character in s1 that matches any character in the string s2. * */ /* squeeze2: delete all characters occ..

Answer to Exercise 2-3, page 46 Solutions by Richard Heathfield and Marshall S McLeish Write the function htoi(s) , which converts a string of hexadecimal digits (including an optional 0x or 0X) into its equivalent integer value. The allowable digits are 0 through 9, a through f, and A through F . Here's my solution: /* Write the function htoi(s), which converts a string of hexadecimal * digits ..

Answer to Exercise 2-2, page 42 Solutions by "Flippant Squirrel" :-) and Craig Schroeder Exercise 2-2 discusses a for loop from the text. Here it is: for(i=0; i

Answer to Exercise 2-1, page 36 Category 0 Solution by Rick Dearman - with corrections by Russ Bobbitt, marked /* RB */ and by Stefan Farfeleder, marked /* SF */ Write a program to determine the ranges of char , short , int , and long variables, both signed and unsigned , by printing appropriate values from standard headers and by direct computation. Harder if you compute them: determine the ran..