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// definition
Array.dim = function(dimention, initial) {
  var a = [], i;
  for (i = 0; i< dimention; i += 1) {
    a[i] = initial;
  }
  return a;
}

// console.log(Array.dim(10, 2));

// p.73
var my_array = Array.dim(2, []);
console.log(my_array);

my_array[0].push(1)
// [ [ 1 ], [] ]
// console.log(my_array);

// p.74
Array.matrix = function(m, n, initial) {
  var a, i, j, mat = [];
  for (i = 0; i < m; i += 1) {
    a = [];
    // for (j = 0; j < n; j++) {
    for (j = 0; j < n; j += 1) {
      a[j] = initial;
    }
    mat[i] = a;
  }
  return mat;
}

var my_matrix = Array.matrix(2, 3, 'a');
// console.log(my_matrix);

Array.identity = function(n) {
  var i, mat = Array.matrix(n, n, 0);
  for (i = 0; i < n; i += 1) {
    mat[i][i] = 1;
  }
  return mat;
}

var my_identity = Array.identity(4);
// console.log(my_identity);

var hoge = {a: 1};
hoge.__proto__ = {c: 3};
console.log(hoge);
console.log(hoge['c']);

// JSON に変換する
var hoge_json =JSON.stringify(hoge);
console.log(hoge_json);
// オブジェクトに復元する
var foo = JSON.parse(hoge_json);

// オブジェクトの状態を更新する
hoge['b'] = 2;

// プロトタイプは保持されない
console.log('hoge', hoge, hoge['c']);
console.log('foo', foo, foo['c']);

console.log('*****')
// for in を試してみる
// var array = [1, 3, 5];
var obj = {a: 1, b: 3, c: 5};
var parent = {e: 7};
parent.__proto__ = {a: 9};
obj.__proto__ = parent;
for (var n in obj) {
  console.log(n, obj[n]);
}