Question about gets()

Code:

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#include <stdio.h>

int main()
{

    char address;

    printf("Enter your address: ");

    gets(address);

    printf("Your address is %s", address);

    return 0;

}

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I really have no idea why there's a 'warning' in this code..
Any help plz..?

The mostly like reason is that gets() expects to receive a pointer which is the address of the first element of an array. It does not expect what you're doing - supplying the value of a single char.

The same goes for the %s format specifier for printf.()


If your compiler is fairly modern, it may also complain about using gets() AT ALL, since gets() was REMOVED from the latest C standard. This is because gets() is dangerous and there is no way for a programmer to make its usage safe. Look up the fgets() function for an alternative.

I'm pretty new to programming and a book said never use gets() in real life, but for an example use it... I understand that, but my compiler (gcc) gave me a segmentation fault when I ran it. So I had to use scanf(). Any ideas on how to fix that?

> I understand that, but my compiler (gcc) gave me a segmentation fault when I ran it
Well that's what you get for ignoring warnings, and passing garbage into functions.

In your code, address is a single character, when what you need is an array. Make address a char array of size 50 (for example), and everything should start to work.

I will add also that the use gets is highly not recommended. Use fgets instead. Information on this is everywhere, even in Wikipedia.

Quote:

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Originally Posted by yuxuantim

So I had to use scanf(). Any ideas on how to fix that?

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Did you even bother to read my previous post?

Okay so...

You have declared "address" as a char.

This reserves enough space for one letter

Code:

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address = 'A';

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gets() tries to put more than one letter at the variable "address": Your computer sees your program trying to modify memory that it doesn't have permission to modify, so it throws a segfault.

Here is a tutorial on how to reserve more than just one char
Arrays in C - Cprogramming.com

Here is a tutorial on strings (which is what you are after) which has an fgets() example.
C Strings - Cprogramming.com

A string (in the C language) is an array of chars where the final character is a Nul '\0' character.
(Note that this is not NULL with 2 L's, as NULL is a pointer which points to nothing FAQ > NULL, 0, \0 and nul? - Cprogramming.com)

The string "Hello" would be stored in an array as,

Code:

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{'H', 'e', 'l', 'l', 'o', '\0'}

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, and the array it is stored would have to have a size of at least 6.