I want to do a function that is able of shift array elements but the arrays can be of ints or of a struct defined by me. How do I iterate on pointers to void arrays?
This is my code so far for this example I'm using Ints but I plan to use the same function with other data types:
void shift(const void *source, int pos, int lenght){
memmove(&source[pos], &source[pos+1], sizeof(int)*(lenght-pos-1) );
}
int main(int argc, char *argv[]) {
int a[10] = {1,2,3,4,5,6};
shift(a, 3, 10);
}
All you need to do to make this work across arbitrary data types is to pass the size of the data as well. This will let you calculate the offset. For example,
void shift(void *source, size_t size, int pos, int length){
int src_offset = pos * size;
int dst_offset = (pos + 1) * size;
memmove(source + src_offset, source + dst_offset, size*(length-pos-1) );
}
Now you can use different data types like so
int main(int argc, char *argv[]) {
// ints
int a[10] = {1,2,3,4,5,6};
shift(a, sizeof(int), 3, 10);
// chars
char b[10] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i'};
shift(b, sizeof(char), 3, 10);
//etc...
}
([0] = 33554433, [1] = 50331648, [2] = 67108864, [3] = 83886080, [4] = 100663296, [5] = 0, [6] = 0, [7] = 0, [8] = 0, [9] = 0). Also the compiler gives: warning: arithmetic on a pointer to void is a GNU extension
[..]operator acts as a dereference. You cannot dereference avoidtype. Your only real option is to cast everything tochar*along with thesizeof (your_type)and adjust the indexing as required.void *you would have a variable of typevoid **, but that's not what you have. You need to show exactly how this function is called. Please update your question with a minimal reproducible example.