function reverse_one_dimensional_array(arr) {
for (let i = 0; i < arr.length / 2; i++) {
tmp = arr[i];
arr[i] = arr[arr.length - 1 - i];
arr[arr.length - 1 - i] = tmp;
}
}
let arr = [1, 2, 3, 4, 5, 6, 7];
reverse_one_dimensional_array(arr);
console.log(arr);
/*
run:
[ 7, 6, 5, 4, 3, 2, 1 ]
*/