C++ structures containing structures SIGSEGV - c++

Question

Let me paste the code first
#include <iostream>
#include <algorithm>
#define MAX 100
using namespace std;
int index;
struct node{
int key;
struct node *up;
int rank;
};
struct edge{
struct node *start, *end;
int weight;
};
struct graf{
struct node *tops[MAX];
int topsAmount;
struct edge *edges[MAX];
int edgesAmount;
};
void makeSet(struct node *z, int key){
z->up = z;
z->rank = 0;
z->key = key;
}
struct node *findSet(struct node *x){
if(x!=x->up)
x->up = findSet(x->up);
return x->up;
};
struct node *returnPath(struct node *x){
cout<<"klucz: "<<x->key<<" ranga: "<<x->rank<<endl;
if(x!=x->up)
{
returnPath(x->up);
}
}
void link(struct node *x, struct node *y){
if(x->rank>y->rank)
{
y->up=x;
}
else
{
x->up=y;
if(x->rank == y->rank)
y->rank++;
}
}
void unionFun(struct node *x, struct node *y){
link(findSet(x), findSet(y));
}
bool acompare(edge lhs, edge rhs) { return lhs.weight < rhs.weight; }
struct edge *MSTKruskal(struct graf *G){
struct edge *A = new edge[MAX];
index=0;
for(int i=0; i<G->topsAmount; i++)
{
makeSet(G->tops[i],0);
}
sort(G->edges[0], G->edges[G->edgesAmount-1], acompare);
for(int i=0; i<G->edgesAmount; i++)
{
if(findSet(G->edges[i]->start) != findSet(G->edges[i]->end))
{
A[index].start = G->edges[i]->start;
A[index].end = G->edges[i]->end;
A[index].weight = G->edges[i]->weight;
index++;
unionFun(G->edges[i]->start, G->edges[i]->end);
}
}
return A;
}
int main()
{
struct node *values[11];
for(int i=0; i<10; i++)
{
values[i] = new node;
makeSet(values[i],i);
}
unionFun(values[0], values[1]);
unionFun(values[2], values[3]);
unionFun(values[1], values[2]);
unionFun(values[5], values[6]);
unionFun(values[7], values[8]);
unionFun(values[3], values[5]);
unionFun(values[0], values[7]);
for(int i=0; i<10; i++)
{
cout<<"sciezka klucza "<<i<<endl;
returnPath(values[i]);
}
struct graf *Graf = new graf;
for(int i=0; i<10; i++)
{
Graf->tops[i] = values[i];
Graf->topsAmount++;
}
struct edge *Edges = new edge[4];
Edges[0].start = values[1];
Edges[1].start = values[2];
Edges[2].start = values[3];
Edges[3].start = values[4];
Edges[0].end = values[5];
Edges[1].end = values[6];
Edges[2].end = values[7];
Edges[3].end = values[8];
Edges[0].weight = 10;
Edges[1].weight = 12;
Edges[2].weight = 11;
Edges[3].weight = 13;
Graf->edges[0] = Edges[0]; //this line was deleted after I found out that I can't compile it
Graf->edges[0]->weight = 0;
return 0;
}
I want to set new graf so firstly in for loop I add tops to my structure and it works then I want to add edges and problem appears. I thought I can just create another array of structures edge and then just set same array in Graf on same values (Graf->edges[0] = Edges[0]; last lines of the code) but it didn't compile, so I wanted to set every value of structure edge in array Graf separately (start = start, end = end etc) but debugger shows SIGSEGV on last line (Graf->edges[0]->weight = 0;) how can I fix it?

Answer 1

Edges[0] has type edge, but Graf->edges[0] has type edge*, i.e. the types are incompatible, which is why the assignment is not allowed.
You probably want to take the address of Edges[0] like so:
Graf->edges[0] = &Edges[0];