The C Language Revision - II
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This is more of my brain dump which I would be using to refer back myself, and, has nothing to do with the original text or ideas of K&R. I am not selling this. And it may contain errors/bugs. You may treat it as a reference or a tutorial or whatever.
The Famous Pointers
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p = &c; p contains address of c, thus, p points to c.
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*p returns what the variable c contains.
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f (char *); is a function "f" whose argument is a pointer to char.
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p = &a; q = &b; p = q; now p points to b.
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f (a); pass by value.
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f (&a); pass by pointers; pass by reference.
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p = &a[0]; *(p + i) gives the value of the i th element in a[].
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p = &a[0]; is same as p = a;
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a[i] is same as *(a + i)
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char b[]; is same as char *b;
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alloc(n), returns a pointer p to n consecutive character positions. Similarly, malloc(n)
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afree(p), releases the storage. Similarly, free(p)
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C guarantees that 0 is never a valid address for data.
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int (*a)[10] : a is an integer pointer to an array with 10 elements.
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int *a[10] : a is an array of 10 pointers to integers.
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f ( int a[10][20] ) = is eqv. to = f ( int a[][20] ) = is eqv. to = f ( int (*a)[20] )
The lines of K&R
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A structure is a collection of one or more variables, possibly of different types, grouped together under a single name for convenient handling.
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A union is a variable that may hold (at different times) objects of different types and sizes (in the single area of storage), with the compiler keeping track of size and alignment requirements.
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Content Copyright (c) 1998-2003
Jagmeet Singh Hanspal.
All Rights Reserved.
