Getting length of character array

Question

I know other questions have been asked about this topic but I could not find one for exactly what I am looking for. I am taking a course on C and was presented with the following challenge: "Create a new application and create four character arrays to hold the following lines of text:

'Roses are Red. Violets Are Blue. C Programming is Fun. And Sometimes Makes my Head Hurt.' Make sure your character arrays are large enough to accommodate the character used to terminate C strings. Using a correctly formatted printf() command and signifier, output the string array values. "

Here is the code I have so far:

#include <stdio.h>

int main()
{

   char firstLine [] = "Roses are red.";
   char secondLine [] = "Violets are blue.";
   char thirdLine [] = "C programming is fun";
   char fourthLine [] = "And sometimes makes my head hurt";
}

Instead of manually counting the number of characters in each array and then putting that number in the "[]", is there a way to determine the length of character in each string?

Justin, following other comments below, get in the good habit of compiling your code with **warnings** enabled in your compile string. At a minimum, something like `gcc -Wall -Wextra -o outputfile inputfile.c` — David C. Rankin, Sep 02 '14 at 03:42

score 3 · Answer 1 · answered Sep 02 '14 at 00:23

The syntax:

char str[] = "Some text.";

already counts the right length for the string . You don't have to take any further action. Leaving the [] empty (in this context) means that the array has the exact size required to store the string.

You can inspect this by doing printf("The size is %zu.\n", sizeof str); , note that this will be 1 more than the result of strlen because strings have a null terminator.

Kick Buttowski · Answer 2 · 2014-09-02T04:27:46.897

1

Based on my research by using strlen

Code:

#include <stdio.h>
#include <string.h>

int main()
{
   char str [] = "Roses are red.";
   size_t len;

   len = strlen(str);
   printf("Length of |%s| is |%zu|\n", str, len);
   return(0);
}

output:

Length of |Roses are red.| is |14|

Source: http://www.gnu.org/software/libc/manual/html_node/String-Length.html

edited Sep 02 '14 at 04:27

answered Sep 02 '14 at 00:10

Kick Buttowski

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Note: `strlen(str)` returns type `size_t`, not `int`. – chux - Reinstate Monica Sep 02 '14 at 00:41
When string are small, you will not encounter differences. In this example --> no problem. For a general solution, yes there is a problem. – chux - Reinstate Monica Sep 02 '14 at 00:44
@chux could you please gimme an example that lead me to problem? – Kick Buttowski Sep 02 '14 at 00:46
2

@KickButtowski Simply declare `len` to be of type `size_t` instead of `int`. – ApproachingDarknessFish Sep 02 '14 at 00:49
@ValekHalfHeart thank you I edited my answer and I read this http://stackoverflow.com/questions/2550774/what-is-size-t-in-c – Kick Buttowski Sep 02 '14 at 00:58
Suggest using `"|%zu|"` Check http://stackoverflow.com/questions/2524611/how-to-print-size-t-variable-portably/2524675#2524675 – chux - Reinstate Monica Sep 02 '14 at 01:45
What did your compiler say? Hint: compare signed-ness of `size_t` and `"%zd"`. If interested, find a draft spec of C11 via http://stackoverflow.com/a/83763/2410359 – chux - Reinstate Monica Sep 02 '14 at 02:57

Getting length of character array

2 Answers2