Question

I’m writing a C program. It compiles fine but when I try to run the binary I get a seg fault. I ran gdb but I got a problem at the following line

*total = a;

The problem is right at the beginning of the code. Here it is:

main(){
  int a[] = {1,1,1,0,0,0,0};
  int **total; //array of int arrays
  *total = a; //i.e. set total's first array to be a.

I’m new to C and pointers. Any help would be appreciated.

Answer 1

total points to a pointer p which points to an int. By assigning to *total, you’re assigning to p. But total hasn’t been initialized, so you’re assigning a value into a random location. You need to initialize total — for example

int * p;
int** total = &p;