Hi
i am now writing a PID controller for a program, but i don't understand few compands, so i can't futher develop my programming
so can anyone help me to explain their functions?
"
if(t>=TDELAY)
{
y[1]= *(OL_out + ol_count_out);
ol_count_out++;
if(ol_count_out==9999)ol_c
}
ol_count_in++;
"
"
double *OL_out;
OL_out = (double *)malloc(10000*sizeof(doub
"
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calvinchan:
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by: zebadaPosted on 2003-01-24 at 12:37:37ID: 7803220
y[1]= *(OL_out + ol_count_out);
Using pointer arithmetic to calculatea memory location.
Whatever the sizeof(*OL_out) is then add that many bytes multiplied by ol_count_out to OL_out and get the value at that memory address and place that value into y[1].
i.e. Assuming OL_out is declared as a double * like this:
double *OL_out;
If the pointer value of OL_out is say, 0x00001234
and if ol_count_out is say, 5 then the value of
*(OL_out+ol_count_out) is the value of the memory location: 0x00001234+(5*8) = 0x0000125C since sizeof(double) is 8 bytes. So the double value that is stored at memory location 0x0000125C will be placed into the y[1] array element.
OL_out = (double *)malloc(10000*sizeof(doub
This statement allocates 10,000 * 8 bytes of memory since sizeof(double) is 8 bytes.
And sets the OL-out pointer to the memory address of the first byte of the allocated memory.
Regards
Paul