Access violation reading location 0xCCCCCCCC

Question

I have problem with my program I don't know what to do :(

double spocitaj(FILE *fr,double **polsum, int *cena){

int r=0, i=0,k=0;
double n=0;
char c;


while((c=getc(fr))!=EOF){
    if(c=='\n') r++;
    if(r==4){
        *cena=k++;
        r=5;
    }
    if(r==6) r=0;       
}

*polsum=(double *)calloc(k,sizeof(double));
r=1;
rewind(fr);

while((c=getc(fr))!=EOF){

    if(c=='\n') r++;
    if(r==4) {
                    ungetc(c,fr);
            fscanf(fr,"%lf", &n);
            *polsum[i]=n;
            i++;
    }
    if(r==6) r=1;       
}

for(i=0;i<*cena;i++)
                    printf("%.2lf\n", *polsum[i]);
return 0;

}

Can you help me please? this is a message: Unhandled exception at 0x012947F8 in Projekt 1.exe: 0xC0000005:

Access violation writing location 0xCCCCCCCC.

Run in the debugger and find the line that throws the exception, then examine the values and compare to what you expect. — Nate Hekman, Apr 04 '13 at 18:58
In main function I have : ...double *polsum; and then I call function spocitaj(fr,&polsum, &cena); — Tomáš Čičman, Apr 04 '13 at 18:59
I'd hate to be the person who has to update/maintain your code! — JBentley, Apr 04 '13 at 19:08
0xCCCCCCCC is uninitialized memory [When and why will an OS initialise memory to 0xCD, 0xDD, etc. on malloc/free/new/delete?](http://stackoverflow.com/q/370195/995714) — phuclv, Apr 28 '15 at 15:46

score 5 · Answer 1 · answered Apr 04 '13 at 19:00

*polsum[i]=n; should be (*polsum)[i] = n;.

*polsum[i] is *(polsum[i]), which treats polsum as an array, but you likely intend it to be a single pointer, a pointer to where there is a double *.

Changing this to (*polsum)[i]) says "Look up the double * that is where polsum points. That double * points to a place where there are many double objects. Get the i^th one.”

Access violation reading location 0xCCCCCCCC

1 Answers1