// 第一种方法
function arrMaxNum2(arr) {
return Math.max.apply(null, arr);
}
function arrMinNum2(arr) {
return Math.min.apply(null, arr);
}
function arrAverageNum2(arr) {
var sum = eval(arr.join("+"));
return ~~(sum / arr.length * 100) / 100;
}
// 第二种方法
function cacl(arr, callback) {
var ret;
for (var i = 0; i < arr.length; i++) {
ret = callback(arr[i], ret);
}
return ret;
}
Array.prototype.max = function () {
return cacl(this, function (item, max) {
if (!(max > item)) {
return item;
} else {
return max;
}
});
};
Array.prototype.min = function () {
return cacl(this, function (item, min) {
if (!(min < item)) {
return item;
} else {
return min;
}
});
};
Array.prototype.sum = function () {
return cacl(this, function (item, sum) {
if (typeof (sum) == 'undefined') {
return item;
} else {
return sum += item;
}
});
};
Array.prototype.avg = function () {
if (this.length == 0) {
return 0;
}
return this.sum(this) / this.length;
};
var theArray = [1, -2, 4, 9, 15];
console.log(theArray.max());
console.log(theArray.min());
console.log(theArray.sum());
console.log(theArray.avg());