1

function printEvery3() {
  for (let i = 1; i <= 88; i += 3) {
    console.log(i);
  }
}

printEvery3();

2

function table9to9() {
  for (let i = 1; i <= 9; i++) {
    for (let j = 1; j <= 9; j++) {
      console.log(i + " x " + j + " = " + i * j);
    }
  }
}
table9to9();

3

function isUpperCase(str) {
  if (str.length == 0) {
    console.log(false);
    return false;
  }
  if (str[0] == str[0].toUpperCase()) {
    console.log(true);
    return true;
  } else {
    console.log(false);
    return false;
  }
}

isUpperCase("ABCD"); // returns true
isUpperCase(""); // returns false
isUpperCase("aBCD"); // returns false

或是

function isUpperCase(str) {
  if (str.length == 0) {
    console.log(false);
    return false;
  }
  return str[0] == str[0].toUpperCase();
}

4

function isAllUpperCase(str) {
  if (str.length == 0) {
    console.log(false);
    return false;
  }

  for (let i = 0; i < str.length; i++) {
    if (str[i] != str[i].toUpperCase()) {
      console.log(false);
      return false;
    }
  }

  console.log(true);
  return true;
}

isAllUpperCase("ABCD"); // returns true
isAllUpperCase(""); // returns false
isAllUpperCase("ABCDEFGHIJKLm"); // returns false

或是

function isAllUpperCase(str) {
  if (str.length == 0) {
    console.log(false);
    return false;
  }

  console.log(str == str.toUpperCase());
  return str == str.toUpperCase();
}

isAllUpperCase("ABCD"); // returns true
isAllUpperCase(""); // returns false
isAllUpperCase("ABCDEFGHIJKLm"); // returns false

5

function position(str) {
  for (let i = 0; i < str.length; i++) {
    if (str[i] == str[i].toUpperCase()) {
      console.log(str[i] + " " + i);
      return str[i] + " " + i;
    }
  }
  console.log(-1);
  return -1;
}

position("abcd"); // prints -1
position("AbcD"); // prints A 0
position("abCD"); // prints C 2

6

function findSmallCount(arr, n) {
  let counter = 0;
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] < n) {
      counter++;
    }
  }
  console.log(counter);
  return counter;
}

findSmallCount([1, 2, 3], 2); // returns 1
findSmallCount([1, 2, 3, 4, 5], 0); // returns 0