C++ dynamic allocation program crashes

Question

I have a very simple piece of code with 2 structures and one dynamic allocation. The program crashes on the "nume" initialization.

typedef struct{
    int key;
    string name;
} TElement;

typedef struct nod {
   int cheie;
   string nume;
   struct nod *stg, *dr;
} NOD;

when i try to do this

void ABC::inserare_element(TElement e){
    NOD *p, *q;
    int n;
    /* construction nod p*/
    n=sizeof (NOD);
    p=(NOD*)malloc(n);
    p->cheie = e.key;
    p->nume = e.name; // on this line the program crashes

Thanks

Answer 1

malloc() will not invoke the constructor of NOD, meaning the constructor of nume will not have been invoked resulting in an attempt to use std::string::operator= on an unconstructed/uninitialized std::string: use new.