On Sunday, 7 June 2015 at 18:59:00 UTC, John Nixon wrote:
While developing with D (DMD64 D Compiler v2.067.0 on MacOS
10.10.3) I had a program with an unexpected behaviour
and I reduced it to the minimal form below. The error as
indicated in the comment is that the function call pvi_calc
changes int_1 when I think it should not. The result copied
below.
I hope this helps. Kind regards
John Nixon
import std.stdio;
int n,cp;
double[] pvi,int_1,int_2;
void pvi_centre(const int centre){
int_1=pvi_calc(centre);
writeln("int_1 = ",int_1);
int_2=pvi_calc(n-1-centre);//pvi_calc is changing int_1!
writeln("int_1 = ",int_1);
return;}
double[] pvi_calc(const int n1){
for(int i=0;i<=n1;++i)pvi[i]= 1;
return pvi;}
int main(){
n=10;
pvi.length=n;
int_1.length=int_2.length=n;
pvi_centre(cp);
return 0;}
~
int_1 = [1, nan, nan, nan, nan, nan, nan, nan, nan, nan]
int_1 = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
There is only one "pvi" array at all. So, pvi_calc function
modifying that only one, and returns it back.
When you first call pvi_calc, int_1 points to pvi array. When you
call it second time, int_2 points to same pvi array again.
Since both of them points to same array, value of int_1 (actually
value of pvi array) changes.
