unsigned char *array[SOME_VALUE];
unsigned char temp = array[0][/*bytes are found here*/];
Array of pointers question
Author
I feel stupid for asking this beings I use pointer all the time but not to this extent.
Here it goes...
I have an array of pointers such as this
This is one way of how to use a char pointer array:
Edit: edited source above a bit
Now array[0] equals the word blah.
Hope this makes sense, if not I can help more.
- BlueDev
[edited by - BlueDev on August 31, 2003 10:56:47 PM]
#include <string.h>void main() { unsigned char *array[255]; unsigned char temp[255]; strcpy(temp, "blah"); // write "blah" to temp array[0] = new char[strlen(temp)+1]; // define array[0] strcpy(array[0], temp); // write temp to array[0] // Do whatever you want with array[] delete [] array[0]; // delete array once your finished}Edit: edited source above a bit
Now array[0] equals the word blah.
Hope this makes sense, if not I can help more.
- BlueDev
[edited by - BlueDev on August 31, 2003 10:56:47 PM]
Author
I understand that. What I need is accessing each byte of each pointer in the pointer array. Hope that makes sense. I want to have a pointer array that holds however many .tga files imagedata that I need to so I can acces each byte for color. Hope that clears up my problem.
Thanks
Thanks
Author
quote:Original post by drekkar
unsigned char tmp = *array[/*element number*/];
But what if I want to access each individual byte in each pointer in the pointer array?
*array[0]//now that I have element 0 I want to access its bytesThanks
ok i think i understand what you are asking now..
unsigned byte specificByte = *(array[0]+#);
where # is the offset of the byte you want to access, 0 is the first (like arrays) 1 is the 2nd etc
// just a quick example of showing how to access them specifically
// this would make the 256 bytes that array[0] is pointing to 255
int i;
for(i=0; i<256; i++){
*(array[0]+i) = 255;
}
[edited by - drekkar on September 1, 2003 1:04:42 AM]
unsigned byte specificByte = *(array[0]+#);
where # is the offset of the byte you want to access, 0 is the first (like arrays) 1 is the 2nd etc
// just a quick example of showing how to access them specifically
// this would make the 256 bytes that array[0] is pointing to 255
int i;
for(i=0; i<256; i++){
*(array[0]+i) = 255;
}
[edited by - drekkar on September 1, 2003 1:04:42 AM]
Author
What if I have a multidim array like this how do I access it for address and for variable value?
Now what I have posted means I have an int array that has int pointers right?
so how do I do this with the posted code above?
thanks
int **ip = new int*[10];for(int x = 0; x < 10; x++)ip[x] = new int[10];for(x = 0; x < 10; x++)delete []ip[x];delete []ip;Now what I have posted means I have an int array that has int pointers right?
so how do I do this with the posted code above?
int *p = new int(10);cout << p << "equals address";cout << *p << "equals value";//how do I go about this with multidim arrays that are allocated dynamically?thanks
its basically the same thing as before but instead of having bytes, it points to a bunch of pointers
*(ip[pointerIndex]+pointerOffset) = value;
pointerIndex is the number from ip[10];
pointerOffset is one of the individual 10 pointers that ip[#] points to
to show the address/value...
cout << "address: " << (ip[0]+0) << endl;
cout << "value: " << *(ip[0]+0) << endl;
the same index/offset thing from above applies to the showing
bagel time ^^
[edited by - drekkar on September 1, 2003 2:48:11 AM]
*(ip[pointerIndex]+pointerOffset) = value;
pointerIndex is the number from ip[10];
pointerOffset is one of the individual 10 pointers that ip[#] points to
to show the address/value...
cout << "address: " << (ip[0]+0) << endl;
cout << "value: " << *(ip[0]+0) << endl;
the same index/offset thing from above applies to the showing
bagel time ^^
[edited by - drekkar on September 1, 2003 2:48:11 AM]
Simple.
You have to keep the size of each array in size_of_array, but that''s inevitable.
But, as the C++ FAQ Lite will tell you, this is the wrong solution to the problem. The real solution would be to use a std::vector of std::vector.
Cédric
for(int i=0; i<nb_array; ++i){ unsigned char *one_array = array[i]; for(int j=0; j<size_of_array[i]; ++j){ cout << one_array[j]; }}You have to keep the size of each array in size_of_array, but that''s inevitable.
But, as the C++ FAQ Lite will tell you, this is the wrong solution to the problem. The real solution would be to use a std::vector of std::vector.
Cédric
Author
Hey Drekkar is this incorrect or correct. It seems to be working both ways?
//your wayfor(int a = 0; a < imageSize; a +=colorMode){ colorSwap = *(imageData[index] + a); *(imageData[index] + a) = *(imageData[index] + (a + 2)); *(imageData[index] + (a + 2)) = colorSwap;}//my wayfor(int a = 0; a < imageSize; a +=colorMode){colorSwap = imageData[index][a];imageData[index][a] = imageData[index][a + 2];imageData[index][a + 2] = colorSwap;}This topic is closed to new replies.
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