How to pass data between angular components?

I can't understand why I'm unable to pass data between two of the components in my Angular app. Here is what I have, but the child component is returning "undefined"

I am created an array of objects that simply take in a string, called profileFeedPosts, and trying to pass that to another component, again as an array of "Post" objects.

profile-feed is the parent, and public-feed is the child. Perhaps I'm missing something about the way parent/child components need to be structured in Angular?

Parent component:

 import { Component} from '@angular/core';
 import { Post } from "../models/post.model"



 @Component({
      selector: 'app-profile-feed',
      templateUrl: './profile-feed.component.html',
      styleUrls: ['./profile-feed.component.css']
    })
    export class ProfileFeedComponent  {

      postBody = null;

      profileFeedPosts: Post[] = [
        new Post("hello")
      ];

      showPostBody(){
        this.postBody = 1;
      }

      createPost(){
        this.postBody = null;
      }

      postSubmitted(post: string){
        const newPost = new Post(post);
        this.profileFeedPosts.push(newPost);
      }

      constructor() { }

      ngOnInit() {
      }

    }

Parent Component HTML:

<div class="post-body" *ngIf="postBody">
  <input id="post" type="text" #userPost placeholder="What's up?">
  <button (click)="createPost(); 
postSubmitted(userPost.value);">Share</button>
</div>
<app-public-feed [childFeedPosts]="profileFeedPosts"></app-public- 
feed>

Child Component:

    import { Component, Input } from '@angular/core';
    import { Post } from '../models/post.model';


    @Component({
      selector: 'app-public-feed',
      templateUrl: './public-feed.component.html',
      styleUrls: ['./public-feed.component.css']
    })

    export class PublicFeedComponent {

      @Input() childFeedPosts: Post[];




      constructor() { }

      ngOnInit() {
      }

    }

    console.log(this.childFeedPosts);