kr-c

I've been going through the K&R C Programming Language book and I'm stuck on Exercise 2-6 which reads: 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. I'm having trouble understanding the exact thing they're looking for me to do. I looked at a possible answer here , but I still don't really understand. I think it's the wording that's throwing me off. Can anyone maybe explain what they're looking for me to do in a different way? I'm hoping that different wording will help me understand

Here's a direct quote from the Book (K&R, 2nd ed, p. 35): "At least the first 31 characters of an internal name are significant. For function names and external variables, the number may be less than 31, because external names may be used by assemblers and loaders over which the language has no control. For external names, the standard guarantees only for 6 characters and a single case." And in C99 there is no length limitation on its internal names, but only the first 63 are guaranteed to be significant (§5.2.4.1 Translation Limits). My question is why are these limits specifically 31 or 63 ?

// K&R syntax int foo(a, p) int a; char *p; { return 0; } // ANSI syntax int foo(int a, char *p) { return 0; } As you see, in K&R style, the types of variables are declared in new lines instead of in the braces. How to convert a K&R function declaration to an ANSI function declaration automatically? Does anybody know such an easy-to-use tool in Linux? You can use cproto or protoize (part of GCC) to generate function prototypes or convert old style (K&R) functions to ANSI format. Since You wanna convert a multiline string, you chould consider perl you have void old_style( c , a ) char c; int a;

The Wikipedia article on ANSI C says: One of the aims of the ANSI C standardization process was to produce a superset of K&R C (the first published standard), incorporating many of the unofficial features subsequently introduced. However, the standards committee also included several new features, such as function prototypes (borrowed from the C++ programming language), and a more capable preprocessor. The syntax for parameter declarations was also changed to reflect the C++ style. That makes me think that there are differences. However, I didn't see a comparison between K&R C and ANSI C. Is