var arr = [45,98,67,57,85,6,58,83,48,18];
console.log('原数组');
console.log(arr);
console.log('sort方法从小到大排序');
console.log(arr.sort(function(a,b){return a-b}));
console.log('sort方法从大到小排序');
console.log(arr.sort(function(a,b){return b-a}));

var arr = [45,98,67,57,85,6,58,83,48,18];
console.log('原数组');
console.log(arr);
console.log('for方法从小到大排序');
console.log(arrSortMinToMax(arr));
console.log('for方法从大到小排序');
console.log(arrSortMaxToMin(arr));
// 找数组中最小的值
function arrMinNum(arr){
var minNum = Infinity, index = -1;
for (var i = 0; i < arr.length; i++) {
if (arr[i]<minNum) {
minNum = arr[i];
index = i;
}
};
return {"minNum":minNum,"index":index};
}
// 返回数组从小到大排序结果
function arrSortMinToMax(arr){
var arrNew = [];
var arrOld = arr.concat();
for (var i = 0; i < arr.length; i++) {
arrNew.push(arrMinNum(arrOld).minNum);
arrOld.splice(arrMinNum(arrOld).index,1)
};
return (arrNew);
}
// 找数组中最大的值
function arrMaxNum(arr){
var maxNum = -Infinity, index = -1;
for (var i = 0; i < arr.length; i++) {
if (arr[i]>maxNum) {
maxNum = arr[i];
index = i;
}
};
return {"maxNum":maxNum,"index":index};
}
// 返回数组从大到小排序结果
function arrSortMaxToMin(arr){
var arrNew = [];
var arrOld = arr.slice(0);
for (var i = 0; i < arr.length; i++) {
arrNew.push(arrMaxNum(arrOld).maxNum);
arrOld.splice(arrMaxNum(arrOld).index,1);
};
console.log(arr)
return (arrNew);
}