在 C++ 中通过引用传递结构不会更新值

Question

i am passing a struct by reference to one function of a class treestr and storing it there in a vector.

Then passing the same struct by reference to another function and performing some computation on data member of struct. This data member gets updated in the original struct but not in the ones stored in the vector.

(Sorry for any mistakes, new to c++, new to stack overflow). Please help.

//Structure description
Struct point{
int x;
int y;
int cal{0};

};

Struct node{

    point p;
    int data; //value to be updated by func

};

int main(){

    treestr * tree= new treestr(); //create object
    int i=0,n=100;
    vector<node> nob;
    while(i<=n){
        p={1,5}; //some values input by user
        node n={p,i};
        nob.push_back(n)//storing the struct node objects seperately in a 
                         //vector
        treestr->insert(n);  //inserting into tree class
        i++;
        }
    //calling func to do some computation on the struct objects inserted
    for(i=0;i<n;i++){
        int x=tree->func(nob[i]);
        cout<<x.cal; //getting updated values from the function
        }

    for(i=0;i<N;i++){
        tree->func2(nob[i]);
    }
    return 0;
}

//class description
class treestr{
    vector<node> buck; 
    insert(node& n){
        buck.push_back(n);
        //store nodes
    }

    func(node& n){
        //calculations
        return n.cal; Value got updated in main.
    }
    func2(node &n){
        int val1=n.cal; //this assigns updated value
        int val2=buck[i].p.cal; //this assigns 0(default value)
        if(val1==val2){ //never matches, val2 is 0 for all objects, val1 is 
                           //not after getting updated
        //do something
         }
    }

};

The cal gets updated in the main function but not in the class where I have stored. Please ignore grammatical and syntactical mistakes, the code returns correct output however this is something that I need to improve my code.

Any possible reasons??

Answer 1

Try changing node n={1,5,0}

to

node * n;
node -> x = 1;
node -> y = 5;
node -> cal = 0;

From what I know of pointers you need to assign each value individually. Also

tree->insert(n)

needs to be

tree.insert(n)

Another thing

int node.cal=tree->func(n);

Not sure what this is supposed to do, but I know it won't work. 'int' needs to be before a variable name. When accessing cal from node your call needs to be an -> and when accessing func from tree it needs to be a .