a = [1, 2, 3, 4, 5]
将数组a原地逆置成 a = [5, 4, 3, 2, 1]
let a = [1,2,3,4,5];
let b = 0;
for (let i = 0, len = a.length; i < (len - 1)/2; i++){
b = a[i];
a[i] = a[len - i - 1];
a[len - i - 1] = b;
}
a = [1, 2, 3, 4, 5]
将数组a原地逆置成 a = [5, 4, 3, 2, 1]
let a = [1,2,3,4,5];
let b = 0;
for (let i = 0, len = a.length; i < (len - 1)/2; i++){
b = a[i];
a[i] = a[len - i - 1];
a[len - i - 1] = b;
}