calc(mesh, prob_data, &cells_fd[crr], species, cr);
I'm looking at a function call in a code, and I just wanted to verify if I am looking this correct. In the above call, I am interested in the argument cells_fd[crr]. Does the "&" in front of the argument mean that cells_fd[crr] is being passed into the function calc, and whatever calc does, will be stored back inside cells_fd[crr]?
cells_fd[crr] is equivalent to *(cells_fd + crr), and thus &cells_fd[crr] is equivalent to &*(cells_fd + crr) which is (cells_fd + crr) as the dereference and address operators cancel out.
Thus, your interpretation is correct in that &cells_fd[crr] passes the address of cells_fd[crr], so that calc() may overwrite the contents, but what calc() actually does with the address is not clear from that single line of code without further context.
"&" it's mean you pass the pointer to call function
i don't know what data type is cells_fd[crr]
#include "stdio.h"
void call( int * i ){
int iValue = *i; //retrieve value saved in pointer
int iResult = iValue * 1000; //any calc
*i = iResult; //save new value in pointer
}
int main(){
int i = 123;
printf("initial value: %d\n", i);
call( &i );
printf("value after: %d\n", i);
return 0;
}
