I'm testing something that we do in school. I have a struct MyStruct and two pointers, but when I want to work with the pointer I get this error for both pointers:
uninitialized local variable 'p' used
struct MyStruct {
int id;
double value;
};
MyStruct *p, *q;
double z = 10;
double y = 16.17;
(*p).value = z;
(*q).value = y;
cout << (*p).value << " " << (*q).value << endl;
Your p and q pointers aren't initialized, so attempting to dereference them is undefined behaviour!
If you really want to use pointers here, make sure you have them point to valid memory. For example:
struct MyStruct {
int id;
double value;
};
MyStruct *p = new MyStruct, *q = new MyStruct; // <- allocate memory with `new`
double z = 10;
double y = 16.17;
(*p).value = z;
(*q).value = y;
cout << (*p).value << " " << (*q).value << endl;
delete p; // <- free memory with `delete`
delete q;
You need to allocate the memory for both p and q structs. What you are doing is trying to access some pointer that doesn't point anywhere.
Add these two lines and don't forget to delete p and q when you're done working with them
p = new MyStruct;
q = new MyStruct;
