C/C++ Programming Help Thread

[califrag]

So many things wrong with both of those, I don't know where to begin @@

don't nitpick i'm trying to get a simple point across not an entire encyclopedia of coding standards.

[Archaemic]

There's a difference between trying to write code that's clean and code that will compile. That won't even compile. Or if it will, it'll give you a mess of warnings and crash instantly when run.

[psp_jono]

I don't see how using "sprintf" and buffers can simplify my code:

My version:

char myCharVariable1 = "Sometext", myCharVariable2 = "MoreText"; int myIntVariable = 2;
printf("%s %02d %s", myCharVariable1, myIntVariable, myCharVariable2);

Your version:

char myCharVariable1, myCharVariable2; int myIntVariable;
sprintf(myCharVariable1, "Sometext");
sprintf(myCharVariable2, "Moretext");
myIntVariable = 2;
sprintf(buffer, "%s %02d %s", myCharVariable1, myIntVariable, myCharVariable2);
printf("%s", buffer);

hmm.. keep using all the sprintf's and buffers you need and i will keep my minimalist approach. Thanks! Plus it all depends on what you are doing and whether your text is static or not, and if it is not static of course you will need to use a sprintf to get your variable initialized with the data you need.

Not nitpicking but i'll just say a couple of things i have noticed from the above posts:

1) As you noted, whether you use a buffer or not depends on if you plan on changing the contents of the string.

- If the string is constant over the entire duration of the program
just use a constant pointer to a string literal.

- If the string changes use a character array and modify the string
with strcpy/sprintf ect.

You could even just have constant string literals and a character pointer that changes which string it points to, it's up to personal preference, there is no wrong or right way.
Keeping things as straight foward as possible like you have is a good idea however :).

2) The string constants in both examples have type 'char', this is incorrect, they should either be a char pointer ('char*' or 'char variable_name[]') or a char array of the appropriate size (char variable_name[size]).

3) You cannot use sprintf to output into a string literal. sprintf is only used to write into a character array defined by the programmer. This is a common mistake, it is important to note that a pointer and an array are not the same thing, the name of an array is a constant pointer but the actual body is a memory space. Before sprintf'ing to a pointer make sure that it points to an array of memory big enough to hold the data.

Hope this helps :)

[califrag]

wow 150 pages into this thread i decide to open my mouth and try to offer some help about a stupid printf function that gerbils can understand. i'm not trying to write code for someone to copy paste into their program and compile immediately.. if i was i'd post the source to hello world. i was simply trying to demonstrate the many different ways that printf can be used WITHOUT sprintf or strcpy or buffers of any kind. the guy I was ORIGINALLY talking to wanted to put static text into his program.. anyways i've learned a lot from this thread.. don't offer any help unless you're just going to copy paste some source code for someone else to copy paste into their program. thanks.

[psp_jono]

??? Sorry to offend, just trying to help mate :)

[califrag]

??? Sorry to offend, just trying to help mate :)

no not you jono you actually kinda backed me up a little thanks, if you notice i made my code more "compileable" for those who are so nitpicky... :)

[myschoo]

ok. im looking for function which would make from string:

hello all

just:

all

basicly, i need to cut away 1st 6 letters? i just cant remeber that function name..... string something

[eldiablov]

I need to know how i would go about doing some animation. Any links ?

[Moca]

ok. im looking for function which would make from string:

hello all

just:

all

basicly, i need to cut away 1st 6 letters? i just cant remeber that function name..... string something

The function you can use is strcpy in the header <string.h>.

Use it like this -

char hello[] = "hello all";
strcpy(hello,hello+6);

What that does is copies the data in the string starting at 6 bytes in front of the address of the array until the null byte is reached. It copies it to the beginning of the string.

You would use the function like this - strcpy(destination,source );

I'll explain a bit more about arrays and whatnot if needed later. for now, I need sleep.

[eldiablov]

Ive been googling but still cannot find anything. Is there any source code i can obtain that will show me the basics and i can then build upon ?

[myschoo]

animation? u can use spritesheet and change coordinates using timer or something similar

Moca: sweet thats what i was looking for. thx

[eldiablov]

A timer is the only way ?

[Coolj]

With OSLib its pretty easy to make animations:)

[eldiablov]

Is OSLib completed for psp ?

btw thanks for the recommendation im reading up now.

[_dysfunctional]

animation? u can use spritesheet and change coordinates using timer or something similar

Moca: sweet thats what i was looking for. thx

char helloStr[10] = "Hello all";
printf(helloStr); // Hello all
helloStr += 6;
printf(helloStr); // all

Would also do the trick.

[Grimfate126]

Is OSLib completed for psp ?

btw thanks for the recommendation im reading up now.

oslib is the most completed library in existance for the psp :)

[pspballer07]

char helloStr[10] = "Hello all";
printf(helloStr); // Hello all
helloStr += 6;
printf(helloStr); // all

Would also do the trick.

I'm gonna throw in another one just for fun.

char *textall;
char texthelloall[] = "Hello All";
textall = strstr(texthelloall,"All");

I am pretty sure that would work

[myschoo]

whats the diffrence between:

char *textall; and char textall;

[Archaemic]

One is a pointer and the other one isn't...

[Grimfate126]

whats the diffrence between:

char *textall; and char textall;

the first one creates a pointer to a char. the name of the POINTER is textall.

the second on creates a char. the name of the CHAR is textall.

[myschoo]

thx. i think i understand :)

[Mr305]

thx. i think i understand :)

How would one change the text under the title?

[Moca]

char helloStr[10] = "Hello all";
printf(helloStr); // Hello all
helloStr += 6;
printf(helloStr); // all

Would also do the trick.

Wait...you can't do that O_o

I kinda see what you are tryin' to do but... You can't modify the address of an array o_O. Unless if I missed something huge.

[myschoo]

How would one change the text under the title?

not possible anymore.
before, premium member could pay it for non-prem.

[_dysfunctional]

Wait...you can't do that O_o

I kinda see what you are tryin' to do but... You can't modify the address of an array o_O. Unless if I missed something huge.

Your right, your right.
It would work as a pointer, but not as a plain array. My mistake.

[psp_jono]

char helloStr[10] = "Hello all";
printf(helloStr); // Hello all
helloStr += 6;
printf(helloStr); // all

Would have worked with the use of another pointer,

char helloStr[10] = "Hello all";
printf(helloStr); // Hello all
char* allStr = helloStr;
allStr += 6;
printf(allStr); // all

or without pointer arithmetic,

char helloStr[10] = "Hello all";
printf(helloStr); // Hello all
char* allStr = &helloStr[6];
printf(allStr); // all

or without storing a pointer at all,

char helloStr[10] = "Hello all";
printf(helloStr); // Hello all
printf(&helloStr[6]); // all

[seenit]

jono wouldn't the last example only display the 6th character not up to the 6th character?

[Archaemic]

I'm fairly certain jono is right on all points in that post.

[psp_jono]

jono wouldn't the last example only display the 6th character not up to the 6th character?

It would print the 6th character and every character following until a null ('\0') character is encountered :).

Heres another one:

char helloStr[10] = "Hello all";
printf( helloStr);                         // prints "Hello all"
printf( helloStr + 6);                   // prints "all"

I'm not a big fan of pointer arithmetic most of the time, it can make code a fair bit harder to understand. Although at times it does make sense to use it.

EDIT: null character was '\n' rather than '\0'. oops :o.

[Archaemic]

Ehh, not quite right on all points this time, jono. \n is the newline character. \0 is the null character.