length of the array of pointers, using strlen in C

[Mif]

Hello.. How do I find the length of this array of pointers?

  char *gCreditsEn[] =
{
	"Title",
	"Game created by:",
	"Game Design:",
	"Music by:",
	"Sounds by:",
	"Game engine:",
	"Game Testers:",
	"",
	"",
	"",
	"Thank you for playing..."
};

if I do:

strlen(*gCreditsEn) - 1;

I get 8, even if I add 300 blank lines after the string "Game Testers:".

I think the right question is how do I calculate the length including even the new lines "" ?

And how do I calculate it at the run time in a loop like this:

for (unsigned int j = gStartLine, k = 0; j < strlen(*gCreditsEn) - 1; j++, k += distBetweenLines)
    {
         ....
          .....
    }

[Mif]

EDIT:

without create a macro:

#define LINES   11

for (unsigned int j = gStartLine, k = 0; j < LINES; j++, k += distBetweenLines)
    {
         ....
          .....
    }

[jonnin]

note: this is a self inflicted problem. Simply putting the length in the array solves it.

#define usefullynamednumber 5
char* foo[usefullynamednumber] = ... etc

and now, forever, you know its length. If you add or remove frome it, change the value. A little more work for the programmer up front, but a lot less weirdness every time you use the thing. A little nicer, you can use an enum to name each index:

enum eforfoo {title, name, date, whatever, efmax};
char* foo[efmax]= {...}; //this auto increments, just add entries to the enum before the last one that gives its size and recompile.
....
printf(.. ,foo[title] ..);

[Mif]

Thank you jonnin I tried even this .. and I know it works, but I don't want to everytime I add a new line to change the MACRO number, I just want it to change using the strlen function, but this "" return <-- nothing from nothing isn't it?

So i need to build something that tells the strlen function when I have the empty quotation to count it as 1 string. Otherwise is simply enough to do this

#define LINES 3

char gCreditsEn[LINES][MAX_PATH] =
{
	"Title",
	"",
	"Thank you for playing..."
};

and then the "" will count as well.

[Mif]

and now the loop is simply than the first time

for (unsigned int j = gStartLine, k = 0; j < LINES; j++, k += distBetweenLines)
    {
if (i >= endPoint)
        {
            if (i <= startPoint - k)
            {
                if (gChangeLang == 0)
                {
                    BlitStringToBuffer(gCreditsEn[j], &g6x7Font, &TextColor, H_CENTER_SCREEN - ((uint16_t)(strlen(gCreditsEn[j]) * 6) / 2), (uint16_t)(i + k), 0);
                }
                else
                {
                    BlitStringToBuffer(gCreditsRo[j], &g6x7Font, &TextColor, H_CENTER_SCREEN - ((uint16_t)(strlen(gCreditsRo[j]) * 6) / 2), (uint16_t)(i + k), 0);
                }
            }
            else break;
        }
    }

[helios]

I don't understand. How could strlen(*gCreditsEn) - 1 == 8?

strlen(*gCreditsEn) - 1
strlen("Title") - 1
5 - 1
4

It obviously tells you nothing of the length of the array of pointers.

Just use C++ types.

const std::vector<std::string> gCreditsEn =
{
	"Title",
	"Game created by:",
	"Game Design:",
	"Music by:",
	"Sounds by:",
	"Game engine:",
	"Game Testers:",
	"",
	"",
	"",
	"Thank you for playing..."
};

[Mif]

but I don't want to use this in the code:

#define LINES 3 

Is there another way to do it ???

is the _countof() MACRO counts even the empty "" ?

[Ganado]

if I do:

strlen(*gCreditsEn) - 1;

I get 8,

This makes no sense. *gCreditsEn means gCreditsEn[0]. gCreditsEn[0]'s string length is 5 (6 if you include the null pointer). Show a minimal example that reproduces your issue.

Also, that's not standard C++. String literal pointers need to be const. (Edit: I suppose you're writing in C? Still, you should use const.)

[AbstractionAnon]

First off, you're going to get warnings for trying to assign const char *s to an array of char *. Change line 1 to const char *.

Your best bet is to use a std::vector. A vector will keep track of the number of lines automatically.

#include <vector>
#include <iostream>
std::vector<const char*> gCreditsEn =
{
	"Title",
	"Game created by:",
	"Game Design:",
	"Music by:",
	"Sounds by:",
	"Game engine:",
	"Game Testers:",
	"",
	"",
	"",
	"Thank you for playing..."
};

int main()
{
	std::cout << "Number of lines = " << gCreditsEn.size();
        for (size_t i = 0; i<gCreditsEn.size(); i++)
		std::cout << gCreditsEn[i] << std::endl;
}

[Mif]

I mean the number of the strings not the "Title" name

char *gCreditsEn[] =
{
	"Title", //0
	"Game created by:", //1
	"Game Design:", //2
	"Music by:", //3
	"Sounds by:", //4
	"Game engine:", //5
	"Game Testers:", //6
	"", //7
	"", //8
	"", //9
	"Thank you for playing..." //10
};

without the 7, 8, 9 there are 8 lines in the array of the pointers..
But yea.. maybe I am wrong to calculate how many strings are with strlen.
Now I realized I did a mistake.

Well then the question is how do I know at run time how many strings are in the array of the pointers without using a MACRO and write it at Compile time ??

[Mif]

Yeah.. I know maybe is simply with C++ types but I only use C.. the title of the question was how to do that in C not C++

[Ganado]

Macros are the crutch that C uses to get by due to it being a duct-taped-together language used to avoid writing directly in assembly.

The following does not use a macro.

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

const char *gCreditsEn[] =
{
	"Title", //0
	"Game created by:", //1
	"Game Design:", //2
	"Music by:", //3
	"Sounds by:", //4
	"Game engine:", //5
	"Game Testers:", //6
	"", //7
	"", //8
	"", //9
	"Thank you for playing..." //10
};

int main(void)
{
    int num_lines = sizeof(gCreditsEn) / sizeof(char*);
    
    for (int i = 0; i < num_lines ; i++)
    {
        if (strlen(gCreditsEn[i]) > 0)
        {
            printf("%s\n", gCreditsEn[i]);
        }
        else
        {
            printf("[empty]\n");
        }
    }
    return 0;
}

I'd put "[C] rest of title" or "C - rest of title" as your title so that people immediately read the "C" part first. That way you'll get less people suggesting you to use vector<string> and such.

[Mif]

Okay that's what I was looking for. Thanks Ganado.
That doesn't mean the other guys don't know the answer, is just me being NOT very explicitly in what I want to obtain , and this sizeof(gCreditsEn) / sizeof(char*); I wrote it soo many times in other code, I don't know what's in my had trying to find the elements of the array of pointers using strlen. Dohh, maybe I need to take a brake sometims :D

Thank you all...

[jlb]

The strlen() function gives you the size of the string.

If you want to know how many strings are in your array you will need to use sizeof, something like:

printf("%zu\n", sizeof(gCreditsEn) / sizeof(gCreditsEn[0]));

[Mif]

Yeah... after Ganado waked me up a bit.. I realized I did a mistake with strlen that tells you the length of a string.
Many thanks..

[seeplus]

You don't need to use possibly expensive strlen() to see if a string is empty or not. If you have the pointer to the string then just test the dereferenced pointer for not 0 if the string is not empty. Consider:

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

const char* gCreditsEn[] =
{
    "Title", //0
    "Game created by:", //1
    "Game Design:", //2
    "Music by:", //3
    "Sounds by:", //4
    "Game engine:", //5
    "Game Testers:", //6
    "", //7
    "", //8
    "", //9
    "Thank you for playing..." //10
};

int main(void) {
    const int num_lines = sizeof(gCreditsEn) / sizeof(char*);

    for (int i = 0; i < num_lines; ++i)
        printf("%s\n", *gCreditsEn[i] ? gCreditsEn[i] : "[empty]");
}

which displays:

Title
Game created by:
Game Design:
Music by:
Sounds by:
Game engine:
Game Testers:
[empty]
[empty]
[empty]
Thank you for playing...

[Ganado]

Sure, but strlen expresses intent better.