Pointer arithmetic for structs

c pointers struct pointer-arithmetic
user950891 picture user950891 · Oct 2, 2011 · Viewed 26.1k times · Source

Given a struct definition that contains one double and three int variables (4 variables in all), if p is a pointer to this struct with a value 0x1000, what value does p++ have?

This is not a homework problem, so don't worry. I'm just trying to prepare for a test and I can't figure out this practice problem. Thanks

This is in C. Yes I want the value of p after it is incremented. This is a 32-bit machine

Answer

tangrs picture tangrs · Oct 2, 2011 
struct foobar *p;
p = 0x1000; 
p++;

is the same as

struct foobar *p;
p = 0x1000 + sizeof(struct foobar);

Related questions

C typedef of pointer to structure

I had come across the following code: typedef struct { double x; double y; double z; } *vector; Is this a valid type definition? The code compiles and runs fine. I was just curious if this is common practice.

Read More
Copying structure in C with assignment instead of memcpy()

Up until recently, I have only seen copying of structure fields done with memcpy(). In classes and online instructions, copying the contents of one struct into another generally looks like struct block *b0 = malloc(sizeof(struct block)); struct block *b1 = …

Read More
Why am I getting this error: "data definition has no type or storage class"?

#include <stdio.h> #include <stdlib.h> struct NODE { char* name; int val; struct NODE* next; }; typedef struct NODE Node; Node *head, *tail; head = (Node*) malloc( sizeof( Node ) ); //line 21 And I compiling like this: cc -g -c …

Read More