C/C++ Programming Help Thread

[Xsjado7]

Hey, iv been messing with the stuff on the computer, setting up a my function. Just a quick question, is it possible to do something like:

char str[32]="Im a string";
string str2;
strcpy(str2, str);

Obviously it doesnt work but is there anything like this?

[daaa57150]

Hey, iv been messing with the stuff on the computer, setting up a my function. Just a quick question, is it possible to do something like:

char str[32]="Im a string";
string str2;
strcpy(str2, str);

Obviously it doesnt work but is there anything like this?

I think this will do it:

char str[32]="Im a string";
string str2(str);

even this works (only to show you that you can do things like that, example above is better for this exact case you have)

char str[32]="Im a string";
string str2=str; //or string str2="Im a string"

of course if you just want to declare a string that is initialized, do it simply like this:

string str2("Im a string");

http://www.cplusplus.com/reference/s...ng/string.html

[yaustar]

char str[32]="Im a string";
string str2( str );
string str3 = str;

[Xsjado7]

Sweet, thanks guys
-= Double Post =-
okay, iv got m function working perfectly on computer but i just put it into my game and i get:

scores.cpp(34) : error: 'string' was not declared in this scope

Iv added -lstdc++ in my makefile so what am i missing?
-= Double Post =-
iv got past that error now, i just had to include <string>. Now im getting a few errors:

source/scores.cpp(57) : error: incompatible types in assignment of 'std::basic_s
tring<char, std::char_traits<char>, std::allocator<char> >' to 'char [128]'
source/scores.cpp(73) : error: incompatible types in assignment of 'std::basic_s
tring<char, std::char_traits<char>, std::allocator<char> >' to 'char [128]'
source/scores.cpp(83) : error: incompatible types in assignment of 'std::basic_s
tring<char, std::char_traits<char>, std::allocator<char> >' to 'char [128]'
source/scores.cpp(93) : error: incompatible types in assignment of 'std::basic_s
tring<char, std::char_traits<char>, std::allocator<char> >' to 'char [128]'
source/scores.cpp(103) : error: incompatible types in assignment of 'std::basic_
string<char, std::char_traits<char>, std::allocator<char> >' to 'char [128]'

those lines consist of:

score.hs1name = loadbuff3.substr(1, seperator-1);

just with a different variable name e.g score.hs2name...
Note: Everything worked fine on the computer

[yaustar]

What datatype is score.hs2name?

[HeadphoneJack]

can anyone help me out, i've been trying to shutdown the psp with the square button and including psppower.h but i dont know what is needed to power off in 3.90 as this call is old afaik

i've been trying

		else if (pad.Buttons & PSP_CTRL_SQUARE)
		{
                  sceSysconPowerStandby();
		}

[Mr305]

int write(int fd, char *Buff, int NumBytes);

Does this work on PSP? Can I use a file descriptor?

[SG57]

Considering your function name is so vague and not in the SDK or STL no *rolls eyes*

[Mr305]

Considering your function name is so vague and not in the SDK or STL no *rolls eyes*

Yeah... It's for dos;
Now-a-days i'm intermixing multiple platforms (3 to be exact)

[_df_]

actually it should work fine. its posix (unistd.h) fwrite works, which just wraps write. just ignore sg57. you can use it.

[cruisx]

ok guys iv been trying to get this right for a few days but have had no luck.

so i have a code for collision right, but i dont know how to correctly modify it so it works for one more sprite on the screen.

this is the code for 1 sprite collision:

if ((img1posX + img1width > img2posX) &&
       (img1posX < img2posX + img2width) &&
       (img1posY + img1height > img2posY) &&
       (img1posY < img2posY + img2height) )

now when i try to modify it for another sprite on the screen, the second sprite still has no collision =\ but the first sprite still does.

my code:

if ((img1posX + img1width > img2posX) &&
       (img1posX < img2posX + img2width) &&
	   (img1posX + img1width > img3posX) &&
       (img1posX < img2posX + img3width) &&
       (img1posY + img1height > img2posY) &&
       (img1posY < img2posY + img2height) )

[Xsjado7]

Spoiler for Post:

What datatype is score.hs2name?

Just realised its a char[32] and not a std::string. Fixed that now. Code compiles but when running i get caught on:

name1 = loadbuff3.substr(1, seperator-1);

Prior to that i have:

separator = loadbuff3.find("|");

Im using the official sony savedata functions so my highscores are loaded as one string. An example of whats stored/loaded:

"032.5=Me|034.9=You|105.0=Someone|096.6=Someoneelse|025.2=Santa"

I have "|" between each highscore. After i have found the first score float with atof() i remove the score and = sign so im essentially left with:

"Me|"

Then i simply find the separator and read from the start of the file to the separator and that gets me the name. Any ideas why this isnt working?

[daaa57150]

What datatype is score.hs2name?

I guess it's a char[128].

the = operator works only in one way:
string = char[] is ok
char[] = string doesn't work

but you can get a const char* from a string with mystring.c_str() if that helps.
-= Double Post =-
xsjado, maybe I can help you with this function:

vector<string> split(string str, string delim)
{
	vector<string> results;
	unsigned int cutAt;
	while((cutAt = str.find_first_of(delim)) != str.npos)
	{
		if(cutAt > 0)
		{
			results.push_back(str.substr(0,cutAt));
		}
		str = str.substr(cutAt+1);
	}
	if(str.length() > 0)
	{
		results.push_back(str);
	}
	return results;
}

it splits a string given a delimiter, and returns it as a vector.
for example, split("032.5=Me|034.9=You |105.0=Someone|096.6=Some oneelse|025.2=Santa", "|") will give you a vector containing this:
"032.5=Me"
"034.9=You"
"105.0=Someone"
etc...
and with the same technique you can get what you want from the string.
-= Double Post =-
cruisx, if you have a working function for collision between 2 sprites, just call it for all your sprites on screen, change the parameters that's all...

[Xsjado7]

I spend two hours learning C++ functions and writing out my function then i log on today to find this

[daaa57150]

I spend two hours learning C++ functions and writing out my function then i log on today to find this

spending time learning is a good thing ;)

[Xsjado7]

Do you know why my code isnt working though? It just gets to:

name1 = loadbuff3.substr(1, seperator-1);

and nothing happens, doesnt do it

[daaa57150]

Do you know why my code isnt working though? It just gets to:

name1 = loadbuff3.substr(1, seperator-1);

and nothing happens, doesnt do it

I'll need the whole function or code block.

[Xsjado7]

  pspDebugScreenInit();
  //This is for the seperator between scores
  int seperator;
  //This is for the "=" sign between the time and name in a highscore
  int equals;
  //The buffer for use with atof
  char* loadbuff2;
  //The buffer for use with string:: functions
  string loadbuff3;
  //For storing the highscore names
  string name1, name2, name3, name4, name5;
  
  //Conversions
  //Convert global.loadbuff for use with string:: functions
  loadbuff3 = global.loadbuff;
  loadbuff2 = new char [loadbuff3.size()+1];
  strcpy(loadbuff2, loadbuff3.c_str());
  pspDebugScreenPrintf("loadbuff3 copied to loadbuff2\n");
  
  //Get first highscore data
  //Get score.hs1
  score.hs1 = atof(loadbuff2);
  pspDebugScreenPrintf("Got time from first highscore\n");

  //Remove score.hs1 from loadbuff3
  loadbuff3.erase(0, 5);
  pspDebugScreenPrintf("Erased furst highscore from loadbuff3\n");

  //Get the seperator from between the data of the first and second highscores
  seperator = loadbuff3.find("|");
  pspDebugScreenPrintf("Found seperator from between highscore 1 and 2\n");

  //Read from six bytes in to the seperator AKA get the name for the first highscore
  name1 = loadbuff3.substr(1, seperator-1);
  pspDebugScreenPrintf("Got first highscore name\n");

[daaa57150]

it's because:
- strings indices start at 0
- substr is like this: string.substr(size_t pos = 0, size_t n = npos) with pos = where to start, n = length of the substring, and not where to stop.

your code (I suppose loadbuff=="Me|"):
name1 = loadbuff3.substr(1, seperator-1);
does this:
name1 = loadbuff3.substr(1, 1);
so name="e".

I haven't tested but maybe try to write name1 = loadbuff3.substr(0, seperator); to see if I'm right.

http://www.cplusplus.com/reference/s...ng/substr.html

[Xsjado7]

Forgot to mention, each float is stored as 5 characters, 3 digits for the seconds, a full stop and one digit for the miliseconds if that helps for anything.

Also its:

name1 = loadbuff3.substr(1, seperator-1);

because i havent removed the "=" sign so its going to be "=Me|".
-= Double Post =-
So does anyone have any ideas as to why the PSP gets caught at using .substr? Doesnt make any sense

[Auraomega]

How do I make a buffer start at a specific memory address of my own choice? I need it for this function:

/**
 * Load a module from a buffer
 *
 * @param buf - Pointer to a buffer containing the module to load.  The buffer must reside at an
 *              address that is a multiple to 64 bytes.
 * @param bufsize - Size (in bytes) of the buffer pointed to by buf.
 * @param flags - Unused, always 0.
 * @param option - Pointer to an optional ::SceKernelLMOption structure.
 *
 * @returns The UID of the loaded module on success, otherwise one of ::PspKernelErrorCodes.
 */
SceUID sceKernelLoadModuleBuffer(void *buf, SceSize bufsize, int flags, SceKernelLMOption *option);

I also keep getting errors when I try and use a function from another module. I've made a module that has all the graphics things I need in order to remove all the libraries from my main code and shrink it, it loads fine and without error, but when I attempt to use the functions it crashes giving me 0x8002013A, library not yet linked. Is there a common fix for this or should I post my makefile and stub?

Thanks.
-Aura

[_df_]

How do I make a buffer start at a specific memory address of my own choice? I need it for this function:

add enough to get it to round to the next size without overflowing the buffer.

uint8_t *buff = malloc( 63 + buffsize);
void *rebase = buff & ~0x3F;

something like that. you'll need the original address to pass to free() so dont throw it away....

[Insert_Witty_Name]

memalign() should work.

[Anti-QuickJay]

I go this

 unsigned int *personapointer=(unsigned int*) (0x004FFE8C+0x08800000);

Now how do I get that value + an offset into a new pointer?

 unsigned int *newPointer=(unsigned int*) (personapointer + 0x0000006E);

?

[Judas]

I go this

 unsigned int *personapointer=(unsigned int*) (0x004FFE8C+0x08800000);

Now how do I get that value + an offset into a new pointer?

 unsigned int *newPointer=(unsigned int*) (personapointer + 0x0000006E);

?

I think you have to add '&', signifying you mean the value of the address the pointer points to, not the pointer itself.

unsigned int *newPointer = (unsigned int*) (&personapointer+0x0000006E);

[Archaemic]

Well, you asked me this over AIM, but you never responded to me after I gave you your answer :/
First off, pointer arithmetic is different. Say you have this:

printf("%u\n",sizeof(some_t));
some_t *pSome = NULL;
pSome += 1;
printf("%u",pSome);

What do you think this would output if the first printf outputs 4?
Here's what it doesn't output:

4
1

Here's what it does output:

4
4

Why? Because "adding one" to a pointer actually adds the size of the pointer. Here's an analogy (that should be unambiguous):

some_t* operator+(some_t *pointer, int incr) {
    return (some_t*)((unsigned int)pointer + (sizeof(some_t)*incr));
}

So yeah, pointer arithmetic is different.

Second, if you actually want to go to the position 0x6E after personapointer, you'd be going to an invalid address for a unsigned int type and would get a bus error if you tried to access the location in memory.

(PS: Judas, that would give you 0x6E positions after the POINTER to personapointer, not what personapointer was pointing to)

[Anti-QuickJay]

Ok, thanx

Sorry about not responding to your AIM, my internet got disconnected for some reason so I just went to play God of War.
:/

[SilverSpring]

How do I make a buffer start at a specific memory address of my own choice? I need it for this function:

/**
 * Load a module from a buffer
 *
 * @param buf - Pointer to a buffer containing the module to load.  The buffer must reside at an
 *              address that is a multiple to 64 bytes.
 * @param bufsize - Size (in bytes) of the buffer pointed to by buf.
 * @param flags - Unused, always 0.
 * @param option - Pointer to an optional ::SceKernelLMOption structure.
 *
 * @returns The UID of the loaded module on success, otherwise one of ::PspKernelErrorCodes.
 */
SceUID sceKernelLoadModuleBuffer(void *buf, SceSize bufsize, int flags, SceKernelLMOption *option);

Thanks.
-Aura

You don't need to choose your own address, just need to make sure your buffer is 64 Byte aligned.

const u8 myModule[MY_MODULE_SIZE] __attribute__((aligned(64))) =
{
    // ...your bin2c'd module... 
};

sceKernelLoadModuleBuffer(myModule, MY_MODULE_SIZE, 0, NULL);

This is a kmode function btw.

EDIT:

I also keep getting errors when I try and use a function from another module. I've made a module that has all the graphics things I need in order to remove all the libraries from my main code and shrink it, it loads fine and without error, but when I attempt to use the functions it crashes giving me 0x8002013A, library not yet linked. Is there a common fix for this or should I post my makefile and stub?

Yea you need to post the stub, specifically your imports attributes flag. Is your lib for umode or kmode exports, or both? Post your exports attributes flag from your exports file as well then.

[homemister91]

Hey guy's,
I can't seem to get my head around some adhoc scaning for my luaplayer.
This is the function so far
void scanadhoc(int *length,void *buf)
{
struct SceNetAdhocctlScanInfo *scaninfo;
/** Scan info structure */
sceNetAdhocctlScan();
sceNetAdhocctlGetScanInfo (length, buf);
}
It compiles well and when called it runs fine but i cant seem to get the adhoc list (the list of availabe adhoc networks to show)
Regards
Homemister
PS and help would be great.

[SG57]

You really haven't given us the problem. You gave us a function that apparently works, not how your using it which is what we need I could write up a quick lua player specific function (the one you add to the array of functions and their name according) if you'd like. I'm busy for like an hour now though :X