Reading string into struct data in C

Question

 typedef struct Node {
   char number[5];
    struct Node *next;
 } Node;   


    char userString[5];
    scanf("%s", userString);

    Node *newNode = malloc(sizeof(Node));
    newNode->number = userString;

I'm trying to read a string entered by the user into "number" in the struct Node, but I'm getting an error that says "assignment to expression with array type". What I can do to fix this?

Use strcpy() to copy a string. Use %4s in the format string to prevent buffer overflow. — Jonathan Leffler
– Jonathan Leffler, Commented Dec 1, 2016 at 6:46
Oh no, here we go again. Don't let cdlane here you suggest strncpy() the padding of the unused space in the array can get costly. — David C. Rankin
– David C. Rankin, Commented Dec 1, 2016 at 6:56
I would suggest properly formatting your code. But I must say... your post was adequately messy to serve as an example, so thank you for that. — MD XF
– MD XF, Commented Dec 1, 2016 at 8:10

Sohil Omer · Accepted Answer · 2016-12-01 07:00:52Z

5

instead of

 newNode->number = userString;

Use strncpy()

 strncpy(newNode->number, userString,sizeof(newNode->number));

Reason why strcpy is needed : newnode->number = userSting , newnode->number is char[] type hence you need to loop and fill all the content byte by byte, while your statement is pointing to the string thats why compiler is giving "assignment to expression with array type"

Now why i have used the strncpy instead of strcpy ... because strncpy limits the bounds of copying.

I hope you understand.

edited Dec 1, 2016 at 7:00

answered Dec 1, 2016 at 6:54

Sohil Omer

1,1817 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

namarino41 Over a year ago

Can you explain why I have to use strcpy() instead of the way that I did it?

namarino41 Over a year ago

Thanks so much for the help!

Starl1ght · Accepted Answer · 2016-12-01 06:47:29Z

2

you need to use strcpy function to correctly copy data from userString to your number array.

answered Dec 1, 2016 at 6:47

Starl1ght

4,5031 gold badge23 silver badges50 bronze badges

Collectives™ on Stack Overflow

Reading string into struct data in C

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related