How do I read values into a structure using pointers?

Question

I know when I have to print I use p->real and so on but what should I write when I am reading numbers using scanf?

#include <stdio.h>

typedef struct {
    int real;
    int imaginary;
} complex;

void read(complex*);

void main() {
    complex c;
    read(&c);
}    

void read(complex* p){
    /*what to write in scanf*/
}

Just a question: are you sure your sturcture members should be int, not float or double? — Benoit
– Benoit, Commented Oct 1, 2010 at 5:18
So I fixed your code's formatting and changed the indentation so it was readable. It's really helpful to people if you do this when you post your original question... — Mark Elliot
– Mark Elliot, Commented Oct 1, 2010 at 5:22
Things posted here are formatted with something called Markdown, you can read about the syntax here: stackoverflow.com/editing-help — Mark Elliot
– Mark Elliot, Commented Oct 1, 2010 at 5:30
Forget scanf exists as it usually buys more trouble than it saves by trying to do two tasks (input and parsing) and does both half-way. fgets and sscanf splits the task and makes parse errors far more easily handled. — msw
– msw, Commented Oct 1, 2010 at 5:35

jbernadas · Accepted Answer · 2010-10-01 05:17:42Z

14

You can write:

scanf("%d %d", &p->real, &p->imaginary);

but that depends heavily on the format in which the numbers come.

answered Oct 1, 2010 at 5:17

jbernadas

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1 Comment

Chris Cooper Over a year ago

I would probably say &(p->real), just for clarity's sake.

Martin Törnwall · Accepted Answer · 2010-10-01 05:30:41Z

6

scanf requires you to pass the address of the memory space you want to store the result in, unlike printf, which only requires the value (it couldn't care less where the value resides). To get the address of a variable in C, you use the & operator:

int a;
scanf("%d", &a);

Meaning: read an integer into the address I specified, in this case the address of a. The same goes for struct members, regardless of whether the struct itself resides on the stack or heap, accessed by pointer, etc:

struct some_struct* pointer = ........;
scanf("%d", &pointer->member);

And that would read an integer into the address of pointer plus the offset of member into the structure.

answered Oct 1, 2010 at 5:30

Martin Törnwall

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Comments

chux · Accepted Answer · 2025-04-24 01:40:15Z

0

You can follow any one of below:

scanf("%d%d",&(*p).real,&(*P).imaginary);

scanf("%d%d",&*p-\>real, &*P-\>imaginary);

edited Apr 24 at 1:40

chux

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answered Apr 22 at 5:48

sekhar d

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1 Comment

Brendan Mitchell Apr 22 at 19:26

This answer looks like a duplicate of existing answers. If your answer adds something significant that has not been covered already, make sure to clarify what that is.

Sumit Singh · Accepted Answer · 2012-09-24 10:33:49Z

-3

Use Following code:

scanf("%d",&pointer->variable);

edited Sep 24, 2012 at 10:33

Sumit Singh

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answered Sep 24, 2012 at 10:08

Desire

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1 Comment

Mike Over a year ago

There's nothing wrong with adding a late answer to a question, but this answer adds nothing to the conservation, it's simply a duplicate of the previous two from two years ago. Please add some additional information when answering questions rather than just copping already accepted answers.

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