Why Null character does not adds up to the end of string when scanf'd?

Question

--start of snip--
char name[15];
...

printf("Enter employee name \n");
scanf("%s",name);

printf("strlen %d \n", strlen(name));
--end of snip --

Output:
Enter employee name
Veronica
8

why is it not adding null character to the end !? am i missing anything?

Please someone explain.

Edited:

Was reading line from opened file using fgets and used strtok(line,"\t ") to get the tokens from the line.

--snip--
char * chk;
char line[100];
char temp_name[15];
while(fgets(line, sizeof line, filep))
{
      chk = strtok(line, " \t");
      while(chk !-= NULL)
      {
           strcpy(temp_name, chk);
           chk = strtok(NULL, " \t");
      }
}
--snip --

Problem:

I am guessing extra character is getting added to the end of the temp_name(not just the name) due to improper handling in strtok delimitter usage.

solution:

if(!strncmp(temp_name, name, strlen(name))) // this is one fix

Other wise use

sscanf(line, "%s", temp_name); //easy fix

Anyways I was confused whether there is problem with NULL or extra character getting added to in strtok operation.

thanks for the answers.

Further, if any one would like to help out what delimiter should i use in strtok to avoid any space, tab etc.

check http://stackoverflow.com/questions/4132849/strlen-in-c-and-c-how-does-it-work — Dimitris Kalaitzis, May 18 '14 at 16:24
If it wasn't there, strlen wouldn't be able to measure the string — Dave, May 18 '14 at 16:24
Also be careful with `scanf`. What happens if usr enters a string with more than 15 chars? — 001, May 18 '14 at 16:28
@Johnny stack overflow would happen, and i would need to put a fix there, right!? Or any better handy solution is there other than putting a check!? — kzs, May 18 '14 at 17:33

score 4 · Accepted Answer · answered May 18 '14 at 16:23

4

The NUL terminator character is added, but strlen returns the length of the string without its NUL terminator.

answered May 18 '14 at 16:23

Teo Zec

383
2
11

score 2 · Answer 2 · answered May 18 '14 at 16:23

2

From man 3 strlen :

The strlen() function calculates the length of the string s, excluding the terminating null byte ('\0').

answered May 18 '14 at 16:23

chrk

4,037
2
39
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score 0 · Answer 3 · edited Jun 23 '14 at 15:07

0

Its there, Null will be added to array at the end of scanf. strlen function will give you number of characters till NULL.It doesn't count NULL during string length calculation

edited Jun 23 '14 at 15:07

BenMorel

34,448
50
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answered May 18 '14 at 16:25

shivakumar

3,297
19
28

Why Null character does not adds up to the end of string when scanf'd?

3 Answers3

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