Why pointer assignment sets all parent pointers above it to the same thing C
state current = state(state::goalState);
current.setEqualTo(OPEN.front());


void state::setEqualTo(const state x){
    this->parent = x.parent;
        for (int i = 0; i < 3; ++i) {
            for (int j = 0; j < 3; ++j) {
                this->board[i][j] = x.board[i][j];
            }
        }
    this->howWeGotHere = x.howWeGotHere;
}

list<state> OPEN;
state current = state(state::goalState);
current.setEqualTo(OPEN.front());
list<state> children = current.generateChildren();
OPEN.splice(OPEN.end(), children);

//State Class
state *parent = NULL;
string howWeGotHere = "";
int board[3][3];

state::state(int x[3][3], state *parent) {
    this->parent = parent;
    for (int i = 0; i < 3; ++i) {
            for (int j = 0; j < 3; ++j) {
                this->board[i][j] = x[i][j];
            }
    }
}

state state::moveLeft() {
int iIndex;
int jIndex;
for (int i = 0; i < 3; ++i) {
    for (int j = 0; j < 3; ++j) {
        if (board[i][j] == 0) {
            iIndex = i;
            jIndex=j;
        }
    }
}
state z = state(board, this);
if (2 == jIndex) {
    return *this;
} else {
    z.board[iIndex][jIndex] = z.board[iIndex][jIndex+1];
    z.board[iIndex][jIndex+1] = 0;
    z.howWeGotHere = "LEFT";
}
return z;
}

state state::moveRight() {
int iIndex;
int jIndex;
for (int i = 0; i < 3; ++i) {
    for (int j = 0; j < 3; ++j) {
        if (board[i][j] == 0) {
            iIndex = i;
            jIndex=j;
        }
    }
}
state z = state(board, this);
if (0 == jIndex) {
    return *this;
} else {
    z.board[iIndex][jIndex] = z.board[iIndex][jIndex-1];
    z.board[iIndex][jIndex-1] = 0;
    z.howWeGotHere = "RIGHT";
}
return z;
}

state state::moveDown() {
int iIndex;
int jIndex;
for (int i = 0; i < 3; ++i) {
    for (int j = 0; j < 3; ++j) {
        if (board[i][j] == 0) {
            iIndex = i;
            jIndex=j;
        }
    }
}
state z = state(board, this);
if (0 == iIndex) {
    return *this;
} else {
    z.board[iIndex][jIndex] = z.board[iIndex-1][jIndex];
    z.board[iIndex-1][jIndex] = 0;
    z.howWeGotHere = "DOWN";
}
return z;
}

state state::moveUp() {
int iIndex;
int jIndex;
for (int i = 0; i < 3; ++i) {
    for (int j = 0; j < 3; ++j) {
        if (board[i][j] == 0) {
            iIndex = i;
            jIndex = j;
        }
    }
}
state z = state(board, this);
if (2 == iIndex) {
    return *this;
} else {
    z.board[iIndex][jIndex] = z.board[iIndex+1][jIndex];
    z.board[iIndex+1][jIndex] = 0;
    z.howWeGotHere = "UP";

}
return z;
}

void state::setEqualTo(const state x){
this->parent = x.parent;
for (int i = 0; i < 3; ++i) {
    for (int j = 0; j < 3; ++j) {
        this->board[i][j] = x.board[i][j];
    }
}
this->howWeGotHere = x.howWeGotHere;
}

list<state> state::generateChildren(){
list<state> children;
state temp(board);
temp.setEqualTo(this->moveUp());
if(*this == temp) {
} else {
    children.push_front(temp);
}
temp.setEqualTo(this->moveDown());
if(*this == temp) {
} else {
    children.push_front(temp);
}
temp.setEqualTo(this->moveLeft());
if(*this == temp) {
} else {
    children.push_front(temp);
}
temp.setEqualTo(this->moveRight());
if(*this == temp) {
} else {
    children.push_front(temp);
}
return children;
}