Copy pointer array values to end of another array in C

Question

This is what I want. I tried it many ways, but not successful. I want to copy 2nd array values to end of 1st array.

uint8_t *set = getCharacterPattern('A');
uint8_t *set2 = getCharacterPattern('B');

// Here I want to copy *set2 values to end of *set array

for (uint8_t i=0; i<(getCharacterSize(A)+getCharacterSize('B')); i++){
    setLed(0,i,set[i]);
}

Please help me someone.

I'm wondering why someone vote down my question... – Chathura Buddhika Nov 30 '14 at 18:06 — Chathura Buddhika, Nov 30 '14 at 18:06

regmagik · Accepted Answer · 2014-11-30T03:13:11.167

1

You need to allocate memory for combined array and copy both arrays into the new memory. I assume getCharacterSize function returns the number of elements in corresponding array.

   // Combine arrays set and set2
   int sizeA = getCharacterSize('A');
   int sizeB = getCharacterSize('B');
   int sizeBoth = sizeA + sizeB;
   uint8_t *bothSets = malloc(sizeBoth * sizeof uint8_t);        
   memcpy(bothSets, set, sizeA * sizeof uint8_t);
   memcpy(bothSets+sizeA, set2, sizeB * sizeof uint8_t);

   // Use combined array
   for (uint8_t i=0; i<sizeBoth; i++){
     setLed(0, i, bothSets[i]);
   }

   // Release allocated memory
   free(bothSets);

edited Nov 30 '14 at 03:13

answered Nov 30 '14 at 02:25

regmagik

574
3
14

The `new` and `delete` keywords are part of C++, not C. – Alex Reynolds Nov 30 '14 at 02:46
Unless you are compiling with a C++ compiler, you do not want to cast the result of `malloc()` in a C program: http://stackoverflow.com/questions/605845/do-i-cast-the-result-of-malloc – Alex Reynolds Nov 30 '14 at 02:56
Sorry to be nitpicky, but C++ is not C and these details really matter. – Alex Reynolds Nov 30 '14 at 02:57
@AlexReynolds, I agree, the details are important. Thanks for correcting me. – regmagik Nov 30 '14 at 03:21

Anonymous · Answer 2 · 2014-11-30T18:48:12.983

0

int len = getCharacterSize('A');
int len2 = getCharacterSize('B');
for (int i=0; i<len+len2; i++)
    setLed(0,i,i<len ? set[i] : set2[i-len]);

edited Nov 30 '14 at 18:48

answered Nov 30 '14 at 01:58

Anonymous

2,122
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Copy pointer array values to end of another array in C

2 Answers2