C/C++ Programming Help Thread

[slicer4ever]

or you can use about.com or just google the command and it comes up with plenty of stuff

[Archaemic]

Sometimes pertaining to different languages...
I just use cppreference.com (C89/C++), cplusplus.com (C89/C++; more in-depth) or opengroup.org (C99) for my reference.

[Moca]

So would you happen to know what to do? I have been testing and patiently waiting for someone to help for hours, and i want to finish this before i do any other optimizations to my shell.

#include <stdio.h>

int main()
{
	FILE* pFile;                  // :|
	pFile = fopen("test.txt","r+b");// Open the file in reading and writing modes :|
	fseek(pFile,5,SEEK_SET); // Goes to 5 bytes after the beginning of the file.
	fprintf(pFile,"0");            // Writes 0 to the 6th byte...
	fclose(pFile);                // :|
	return 0;                     // :|
}
/*
 Before:
		123456789
 After:
		123450789
*/

-_-

[slicer4ever]

what is "r+b"? i only know of "r+"

[Moca]

what is "r+b"? i only know of "r+"

Open it in binary mode instead of text mode. If you dont specify b, it will likely open a file in text mode.

[Access_Denied]

Open it in binary mode instead of text mode. If you dont specify b, it will likely open a file in text mode.

I think you're just supposed to use "rb", not "r+b". But they probably do the same thing.

[Archaemic]

No, they don't. r+b is read/write binary mode. You can't use write functions with rb as your mode.

[Moca]

I think you're just supposed to use "rb", not "r+b". But they probably do the same thing.

As the Archaemic said...

r and r+ are different.
r means read only
r+ means read and write

b means binary mode

rb means read in binary mode
r+b means read and write in binary mode

[slicer4ever]

r+b was the only one i hadn't seen and i didn't put one and 2 together

[SuperBatXS]

Oh, i didn't know you could do read and write and binary mode all together....thanks Moca, now it makes sense.

[slicer4ever]

edit: nvm

[SuperBatXS]

Hey guys, thanks for helping me learn file i/o writing x to y bytes. Thanks to you guys, my project is going great. Btw, i made a guide for people who would have trouble with this:

Post some C samples

[Moca]

Hey guys, thanks for helping me learn file i/o writing x to y bytes. Thanks to you guys, my project is going great. Btw, i made a guide for people who would have trouble with this:

Post some C samples

Dammnit i wish i had developer status :|

[BlackShark]

The first thing that comes to mind is fread + strcmp
fseek(file,-4,SEEK_END); // Seeks -4 bytes from the end of the file

Then read the four bytes with fread and store it in a string. Compare the string with "mp3" and if strcmp returns 0, they are equal.

btw, i guess you could read the header of every file in a directory then work from there.

IC, so what I would do is

if (fseek(gameEntry[current_selection].name,-4,SEEK_END) == ".mp3") {
                                   MP3_Init();
                                   MP3_Load(gameEntry[current_selection].path);
                                   MP3_Play();
                     }
                }

Correct?

[SuperBatXS]

Dammnit i wish i had developer status :|

Remember one thing: developer status is what you need to strive for. I personally don't know you, but my advice to you is that releasing a good app doesn't always earn you dev status- you have to be smart in a lot of coding fields. I personally think you should be a dev, but just some advice for you. ;)

[Access_Denied]

There's one problem with your example Superbatxs. What if you don't know exactly where the 5 is? Here's an example that will replace the first 5 in the file with a 0. And it doesn't matter where it is in the file.

#include <stdio.h>

int main() {
     FILE* foo = fopen("foo.txt","r+b");
     for(;;) {
          int get = fgetc(foo);
          if(get == 53) {
               fprintf(foo,"0");
               break;
          }
          if(get == EOF) {
                  printf("There is no 5 in the file.");
                  sceKernelDelayThread(5*1000*1000);
                  sceKernelExitGame();
          }
     }
     fclose(foo);
     sceKernelExitGame();
}

EDIT: Turns out that particular code doesn't work, but you get the idea.

[Raphael]

Remember one thing: developer status is what you need to strive for. I personally don't know you, but my advice to you is that releasing a good app doesn't always earn you dev status- you have to be smart in a lot of coding fields. I personally think you should be a dev, but just some advice for you.

No, not really. Dev status is more a random title than anything strived for, or measuring your smartness in "a lot of coding fields". Actually, it doesn't mean anything on these forums, but that the person has released any two or three end-user titles, be it a LUA pixel unstucking script or a full-blown Shell in C. It's as giving the title scientist to anyone that ever wrote an essay in school, while at the same time real scientists that do mainly background work don't get the title, for the plain reason that some newspaper columnists didn't recognize that work.

BTW: Quoting yourself in your sig is the same as masturbating to your own picture.

[MaTiAz]

BTW: Quoting yourself in your sig is the same as masturbating to your own picture.

If it wasn't 2:39AM in here, I would've bursted to a very loud laugh

[Moca]

IC, so what I would do is

if (fseek(gameEntry[current_selection].name,-4,SEEK_END) == ".mp3") {
                                   MP3_Init();
                                   MP3_Load(gameEntry[current_selection].path);
                                   MP3_Play();
                     }
                }

Correct?

Incorrect. You dont compare strings with ==.

You use strcmp(string1,string2);

if(strcmp(string1,string2) == 0)
{
    printf("The strings %s and %s are equal \n",string1,string2);
}

[Access_Denied]

Remember one thing: developer status is what you need to strive for. I personally don't know you, but my advice to you is that releasing a good app doesn't always earn you dev status- you have to be smart in a lot of coding fields. I personally think you should be a dev, but just some advice for you. ;)

Honestly, there are only about 15 people on this entire forum that should have dev status. Me, not being one of them.

[SuperBatXS]

There's one problem with your example Superbatxs. What if you don't know exactly where the 5 is? Here's an example that will replace the first 5 in the file with a 0. And it doesn't matter where it is in the file.

#include <stdio.h>

int main() {
     FILE* foo = fopen("foo.txt","r+b");
     for(;;) {
          int get = fgetc(foo);
          if(get == 53) {
               fprintf(foo,"0");
               break;
          }
          if(get == EOF) {
                  printf("There is no 5 in the file.");
                  sceKernelDelayThread(5*1000*1000);
                  sceKernelExitGame();
          }
     }
     fclose(foo);
     sceKernelExitGame();
}

EDIT: Turns out that particular code doesn't work, but you get the idea.

The purpose of my tutorial wasn't really to find a five and replace it with something. It was to write X to Y bytes in a file. Yea, you may be thinking that it's the same thing.....but let me put it in a different way (sorry i am bad at wording). It was also to find any number without knowing it, yet if you know its position in the file, then you replace it....um......well i don't know how else to put it. I had to use it for my G-Pack config file though, let's just say that.

No, not really. Dev status is more a random title than anything strived for, or measuring your smartness in "a lot of coding fields". Actually, it doesn't mean anything on these forums, but that the person has released any two or three end-user titles, be it a LUA pixel unstucking script or a full-blown Shell in C. It's as giving the title scientist to anyone that ever wrote an essay in school, while at the same time real scientists that do mainly background work don't get the title, for the plain reason that some newspaper columnists didn't recognize that work.

BTW: Quoting yourself in your sig is the same as masturbating to your own picture.

I definitely agree with your first paragraph. However, i must say that saying that "Quoting yourself in your sig is the same as masturbating to your own picture" is just RUDE. I don't even know you, and why the hell are you being so mean??? Just keep your comments to yourself.......and btw, i can say some pretty mean things about you by just looking at your posts and your personality. I can keep that quote if i want, and i need to express myself by quoting myself, and showing kindness and love to other developers, then masturbation isn't exactly the situation

Honestly, there are only about 15 people on this entire forum that should have dev status. Me, not being one of them.

I definitely agree....with most of it. I agree that there are many people without dev status, however, i think you deserve it too. ;)

[GuitarGod1134]

this isnt really psp related but its C++. is anyone familiar with allegro? if so then can you plz help me out here.
if not then i will just go to the allegro board but im making a game. and all goes well compiled and everything then upon running the game i get that stupid error report from windows asking if i want to send an error report. the last time i got this with a game i was making was when one of the pics was wrongly named and thus couldnt be loaded. if anyone knows what my problem is that would be nice but if not then thats ok becaues i realize this isnt really psp related.

Spoiler for Spoiler for code:

//lets begin with the header
#include <allegro.h>

//declare our pics
//these are pics for our charactor
BITMAP *charupSprite;
BITMAP *chardownSprite;
BITMAP *charleftSprite;
BITMAP *charrightSprite;

//our player coordinates on the screen
int playerx = 10;
int playery = 10;

//players direction to correspond with the sprite
int dir = 1;

//main function
int main()
{
    //initiate the usual allegro stuff
    allegro_init();
    install_keyboard();
    set_color_depth(16);
    set_gfx_mode( GFX_AUTODETECT, 640, 480, 0, 0);
    
    //lets get a loop going so when the person presses
    // esc he/she can quit the game
        while ( !key[KEY_ESC])
    {
    //charactor pics
charupSprite = load_bitmap("charup.bmp", NULL);
chardownSprite = load_bitmap("chardown.bmp", NULL);
charleftSprite = load_bitmap("charleft.bmp", NULL);
charrightSprite = load_bitmap("charright.bmp", NULL);
    //clear the key buffer so its free of memory
    clear_keybuf();
    //acquire the screen
    acquire_screen();
    
    //lets set up the movement for the player
    if (key[KEY_UP]) dir = 1, --playery;
    else if (key[KEY_DOWN]) dir = 2, ++playery;
    else if (key[KEY_RIGHT]) dir = 3, ++playerx;
    else if (key[KEY_LEFT]) dir = 4, --playerx;
    
    //now the actual blitting of the picture to the screen
    //all the statements are for directions
    if (dir == 1)
    {
        draw_sprite( screen, charupSprite, playerx, playery);
    }
    else if (dir == 2)
    {
        draw_sprite( screen, chardownSprite, playerx, playery);
    }
    else if (dir == 3)
    {
        draw_sprite( screen, charrightSprite, playerx, playery);
    }
    else if (dir == 4)
    {
        draw_sprite( screen, charleftSprite, playerx, playery);
    }
    
    //end the while
    }
    
    //finish it off
    release_screen();
    return 0;
}

//end the main
END_OF_MAIN();

its not even that far into developement. and i still get this error.

[Raphael]

I definitely agree with your first paragraph. However, i must say that saying that "Quoting yourself in your sig is the same as masturbating to your own picture" is just RUDE. I don't even know you, and why the hell are you being so mean??? Just keep your comments to yourself.......and btw, i can say some pretty mean things about you by just looking at your posts and your personality. I can keep that quote if i want, and i need to express myself by quoting myself, and showing kindness and love to other developers, then masturbation isn't exactly the situation

Sorry, I wasn't trying to be rude or sth. but that's just my opinion. Quoting yourself is an act of egomania (independent of the context), hence the (meant to be more funny than offensive) analogy to masturbation.
Anyway, you're free to express your own opinion about me if you feel fit for it.
And yes, you're also totally free to keep that quote in your sig. I'm not god telling you you'll get to hell if you don't remove it or sth, I'm just a random person on the net telling you that I find it [InsertMeanWord] without any further consequences for you if you don't fit my opinion.

[hallo007]

strcat ( temp , filename );
strcat ( temp , "/" );
sceIoMkdir(temp, 0777);

let's say filename is "ms0:/PSP/test" for example
why doesnt this work? (it doesnt make the folder test)

[Archaemic]

I don't think you're supposed to end the filename with a slash.

Check the return value of sceIoMkdir.

[hallo007]

aargh,oke that was stupid of me thnx

[Kwastie]

i am busy creating a nice menu; and now i want it to give it some nice color's i know how but it's a hell of job..
it's
pspDebugScreenSetTextColo r(0000CD); for the
printf(" ->");
pspDebugScreenSetTextColo r(FF0000);
printf(" menu option 1\n");
pspDebugScreenSetTextColo r(7FFF00);
printf(" menu option 2\n");
printf(" menu option 3\n");
printf(" menu option 4\n");

just for this with color's of:
-> menu option 1
menu option 2
menu option 3
menu option 4
is there any way i can make this easyier?
like printf("menu option 2",blue);?
and printf(" ->",geen);
could somehelp me with this?

[Archaemic]

#define GREEN 0x00ff00
#define BLUE 0x0000ff
/*et cetera*/
int menuPrintf(char *string, u32 color) {
    pspDebugSetTextColor(color);
    return printf("%s",string);
}

Yes, it's that easy.

[Kwastie]

Thanks allot
-= Double Post =-
and if got 2 more question's
-I alsow want to print nickname, what is the most easy way to this?
-and how do I halt a script.. first the user has to push X continue
example:
The creating of this program is not resposible for any damage to your psp.
if you agree press START
if you don't agree press X
if (pad.Buttons & PSP_CTRL_START) {
menu();
}
else if (pad.Buttons & PSP_CTRL_CROSS) {
sceKernelExitGame();
}
else {
sceKernelSleepTread();
}
something like this, i am not sure about else if

[hallo007]

-check the sdk samples!!!!!!!

-sceKernelDelayThread(1000 000);
1000000= one second

-use code tags , thank you!