I am trying to build wall that prints when you say on width of (0) or 9 or so

I tried if(j==0) instead of j==[0] but it is just printing wall, then I can't print object because of the for |\n wall I need x y coordinator.

#include<iostream>
using namespace std;

int main(){
    int wallx, wally, obx, oby;
    const int length=10;
    const int width=10;
    for(wallx=0; wallx<width;wallx++){
        cout<<" _";
    }
    cout<<endl;
    //building wally but I want wally to print | on width of 0
    for (int i[]={0}; i{}<width; i{++}}{
        if(j==[0]){
            cout<<"|\n";
        }
    }