Exercise 3-1

Our binary search makes two tests inside the loop, when one would suffice (at the price of more tests outside). Write a version with only one test inside the loop and measure the difference in run-time.

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Exercise 3-2

Write a function escape(s,t) that converts characters like newline and tab into visible escape sequences like n and t as it copies the string t to s . Use a switch . Write a function for the other direction as well, converting escape sequences into the real characters.

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Exercise 3-3

Write a function expand(s1,s2) that expands shorthand notations like a-z in the string s1 into the equivalent complete list abc…xyz in s2 . Allow for letters of either case and digits, and be prepared to handle cases like a-b-c and a-z0-9 and -a-z . Arrange that a leading or trailing - is taken literally.

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Exercise 3-4

In a two’s complement number representation, our version of itoa does not handle the largest negative number, that is, the value of n equal to -(2 to the power (wordsize - 1)) . Explain why not. Modify it to print that value correctly regardless of the machine on which it runs.

It doesn’t handle it because it assumes that the first bit is the negative or positive sign.

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Exercise 3-5

Write the function itob(n,s,b) that converts the integer n into a base b character representation in the string s . In particular, itob(n,s,16) formats n as a hexadecimal integer in s.

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Exercise 3-6

Write a version of itoa that accepts three arguments instead of two. The third argument is a minimum field width; the converted number must be padded with blanks on the left if necessary to make it wide enough.

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