let i = 0;
let sum = 0;
while (i < 100) {
  sum = sum + i;
  i = i + 1;
}
console.log(sum);

let s = "";
let j = 0;
while (j < 4) {
  s = s + `[${j}]`;
  j = j + 1;
}
console.log(s);