Chapter 3 Exercises

SabineB · October 18, 2020, 4:47pm

<script>
//BEAN COUNTING 2
var string = prompt("Enter your string");
var character = prompt("Enter character which should be counted");
var count = 0;
function countChar(string, character){
  for (N=0; N < string.length; N++){
    if (string[N] === character){
      count++
    }
}
console.log(count);
}

countChar(string, character);

</script>

CryptoEatsTheWorld · October 19, 2020, 3:32am

Recursive function example:

  function isEven(num) {
    num = Math.abs(num);
    if (num == 0) { return true; }
    else if (num == 1) { return false; }
    else { 
      num = num - 2;
      return isEven(num);
    }
  }

  isEven(2);

CryptoEatsTheWorld · October 19, 2020, 3:50am

BEAN COUNTING

function countBs(chars, letter) {
    let amount = chars.length;
    let count = 0;

    for (i = 0; i < amount; i++) {
      if (chars[i] == letter) {
        count++
      }    
    }
    return count;
  }

  countBs("Boys", "s");

icecoff · October 19, 2020, 10:01am

1.function min(a, b){

if(a<b){
    return a;
}else{
    return b;
}
return min(a,b);

}
2.
function isEven(number){
if(number==0){
return true;
}else if(number ==1){
return false;
}else if (number<0){
return isEven(number+2);
}else{
return isEven(number-2);
}
}
}
3.
function countBs(str){

function countChar(n,Bs){
   
    x=str.length;
    if (n==x){
        
        return Bs ;
    }else if(str[n]=='B'){
        
        return countChar(n+1, Bs+1);
    }else {
        
        return countChar(n+1, Bs);
    }
}

return countChar(0, 0) ;

}

Bossman · October 20, 2020, 5:52am

Exercises

Minimum:

function getMin(n1, n2) {
  let minNbr;

  if (n1 < n2) {minNbr=n1;} else {minNbr=n2;};
  return minNbr;
};

Recursion:

function isEven(nbr) {
    if (nbr == 0) {
      return true;
    } else if (nbr == 1) {
      return false;
    } else if (nbr < 0) { return "Not a valid nbr!!!";};  
    } else {
      return isEven(nbr-2);
    };
};

Beans:

function countBs (str) {
  let cnt = 0;
  for (i=0; i<str.length; i++) {
    if (str[i] == "B") {cnt++;};
  };
  return cnt;
};

countBs("alibaBBa");


function countChar(str, char) {
  let cnt = 0;
  for (i=0; i<str.length; i++) {
    if (str[i] == char) {cnt++;};
  };
  return cnt;
};

RikkeHrab · October 22, 2020, 3:17pm

Minimum:
// Your code here.
function min(a,b) {
if (a < b) {return a;}
else {return b}
}
console.log(min(0, 10));
// → 0
console.log(min(0, -10));
// → -10

RikkeHrab · October 22, 2020, 3:18pm

Recursion:
// Your code here.
function isEven(n) {
if (n == 0) return true;
else if (n == 1) return false;
else if (n < 0) return isEven(-n);
else return isEven(n - 2);
}

console.log(isEven(50));
// → true
console.log(isEven(75));
// → false
console.log(isEven(-1));
// → ??

RikkeHrab · October 22, 2020, 3:19pm

Bean Counting:
// Your code here.
function countBs(string) {
return countChar(string, “B”);
}
function countChar(string, char) {
let count = 0;
for (let a = 0; a < string.length; a++) {
if (string[a] == char) {
count += 1;
}
}
return count;
}
console.log(countBs(“BBC”));
// → 2
console.log(countChar(“kakkerlak”, “k”));
// → 4

camarosan · October 23, 2020, 1:20am

1. Minimum

2. Recursion

3.Bean counting

serba · October 24, 2020, 10:54pm

// function Math.max takes any amount of arguments and gives the largest.

console.log(Math.max(2,4));

// function Math.min takes two arguments and returns smallest.

console.log(Math.min(2,4));

// write a function min that takes two arguments and gives the minimum

function min(a,b){
if(a < b) {
return a;
}
else {
return b;
}
}
console.log(min(4,5));

// create a function to accept a single parameter and return a Boolean.

function isEven(n) {
if(n == 0){
return true;
}
else if(n == 1){
return false;
}
else if(n < 0){
return isEven(-n);
}
else {
return isEven(n - 2);
}
}
console.log(isEven(50));
console.log(isEven(75));
console.log(isEven(-1));

JBravo · October 25, 2020, 4:40am

FIND MINIMUM

  function minimum(a,b){
    if ((a-b) < 0){
      return a;
    }else {
      return b;
    }
  }
  var a = Number(prompt("Which is the first number? "));
  var b = Number(prompt("Which is the second number? "));

  alert("The minimum number is " + minimum(a,b));

EVEN/ODD

  function isEven(n){
    var num = n;
    while(n >= 0){
      if(n == 0){
        alert(num + " is EVEN");
      }
      if (n==1) {
        alert(num + " is ODD");
      }
      n = n-2;
    }
  }

  let n = Number(prompt("Give me a number: "));
  if (n < 0) {
    alert(n + " is a negative number");
  }else {
    isEven(n);
  }

BEAN COUNTING

function countLetter(w,l){
  letterCount = 0;
  for (var i = 0; i < w.length; i++) {
    if (w[i] == l) {
      letterCount++;
    }
  }
  alert("The word -" + w + "- has " + letterCount + " " + l + " charachters.");
}


  let word = prompt("Write a word: ");
  let letter = prompt("Which letter do you want to count? ");
  console.log(word);

  countLetter(word,letter);

Agnie · October 26, 2020, 12:12pm

// Chapter 3 exercise 1

function MinNumber(a,b){
if(a<b){
document.write (a)
}
else{
document.write(b)
}
}

MinNumber(4,45);

// Chapter 3 exercise 2

function isEven(n) {
if (n == 0) return “even”;
else if (n == 1) return “odd”;
else if (n < 0) return isEven(-n);
else return isEven(n - 2);
}

console.log(isEven(30));

// Chapter 3 exercise 3

function countBs(string){
var count = 0;
for (var a = 0; a < string.length; a++){
if (string[a] == “B”) {
count += 1;
}
}
}

countBs(“BBdesf”);

Amri2020 · October 28, 2020, 4:11pm

MINIMUM

function min(a,b){
if (a<b){
return a;
} else {
(a>b)
return b ;
}
}

RECURSION

My first solution was to solve the exercise with the remainder operator.

function isEven(N){
if (N%2 == 0) {
return “even”;
else
return “odd”;
}
}
…but after reading the question again … I came up with this solution.

function isEven(n){
if (n === 0){
return true;
} else if { n === 1){
return false;
} else {
return isEven(n-2);
}
}

BEAN COUNTING

function countBS(string){
let count = 0;
for (let n = 0; n < string.length ; n +=1){
if (string.charAt(n) === “B”)
count +=1;
}
return count;
}

function countChar(string,c){
let count = 0;
for (let n = 0; n < string.length; n+=1){
if (string.charAt(n) === c )
count +=1;
}
return count;
}

RCV · October 28, 2020, 5:28pm

Exercise 1

function min(x,y){
if (x<y){
return x;
}else return y;
}
console.log(min(3,5));
console.log(min(5,3));

Exercise 2

Exercise 3

I had to look at the answers for the last one, it took me several attempts and several reads through the material to understand it but I get it now!!

Johnb3 · October 29, 2020, 6:00am

Q 1. “Write a function min that takes two arguments and returns their minimum.”

ANS:

  function isMin(w, x) {
	if(w < x)
      return w;
  		else return x;
}
		console.log(isMin(205, 306));
		
		console.log(isMin(2432, 1805));

// 205
// 1805

Q 2. Write a recursive ‘isEven’ function that accepts a single number parameter and returns a boolean.

ANS:

    function isEven(num){
   
        if(num == 0)
          return true;
  else if(num == 1)
          return false;
  else if(num < 0)
          return isEven(-num);
     else
          return isEven(num-2);

}

// test # 1 (negative 1)
console.log(isEven(50))
= true
console.log(isEven(75))
= false
console.log(isEven(-1))
= false

// test # 2 (negative 2)
console.log(isEven(50))
= true
console.log(isEven(75))
= false
console.log(isEven(-2))
= true

Q 3. write a function called countChar that behaves like countBs, except
it takes a second argument that indicates the character that is to be counted
(rather than counting only uppercase “B” characters). Rewrite countBs to
make use of this new function.

ANS:

      function countChar(string, ch) {
	         var counted = 0;
               for(var i = 0; i < string.length; i++)
                if(string.charAt(i) == ch)
                 counted += 1;
  	             return counted;
}

      function countBs(string) {
          return countChar(string, "B")
}

	console.log(countBs("BbbBBbBBbbBBBbbB"));
              = 9
	console.log(countChar("jjjJJJjjJjjJjJjjjJjJj", "J"));
              = 8

Ebad1416 · October 30, 2020, 5:10am

1. min() function:

  if (a <= b) return a;
  else return b;
}
console.log(min(-3,4));  //output: -3

2. Recursion:

function isEven(n){
   if(n == 0) return true;
   else if (n == 1) return false;
   else if (n < 0) return isEven(-n);
   else return isEven(n-2);
}
console.log(isEven(30));
console.log(isEven(57));
console.log(isEven(-81));
// Output: True, False, False

3. Bean Counting:

function countBs(str,char)
{
//str = toString(str);
let counter=0;
for (let i=0; i < str.length; i++)
  {
    if (str[i]== char) counter++;
  }
return counter;
}
console.log(countBs("BBDHJJLKJJFBBWKEHGBBEBB" , "B"));
// Output: 8

Daniel_Jude · November 1, 2020, 8:01pm

/*
1.
function findMin(x,y,z){
if (x > y) {
return z + y + 5;
}
else
return x + z + 3;
}
console.log(findMin(6,3,2));

2.

function isEven(n){
if (n % 2 === 0){
return true;
} else {
return false;
}
}
console.log(isEven(50));
console.log(isEven(0));
console.log(isEven(-1));

3.
function countBs(string){
let result = 0
for (let i = 0; i <= string.length; i++){
if (string[i] === ‘B’){
result = result + 1
}
}
return result;
}
function countChar(string, character){
let result = 0
for (let i = 0; i <= string.length; i++){
if (string[i] === character){
result = result + 1
}
}
return result;
}
console.log(countBs(“BoBBheBuilBer”));
console.log(countChar(“llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch”, “l”));

*/

bjamRez · November 2, 2020, 9:59pm

Minimum

function minFunction(a, b) {
var toReturn = 0;
if(a < b) {
toReturn = toReturn + a;
}
if(b < a) {
toReturn = toReturn + b;
}

return toReturn;
}

var testMinFunction = minFunction(3, 5);
console.log(testMinFunction); // returns 3

bjamRez · November 2, 2020, 9:52pm

Recursion

function isEven(n) {
if (n == 0) return true;
else if (n == 1 || n == -1) return false;
else return isEven(n - 2);
}

console.log(isEven(-1)); // -1 fix returns “false”

bjamRez · November 2, 2020, 9:56pm

Bean Counting (I was not able to figure this one out but here is what I did)

var str = “BeN”;
//var n = str.length; // this maybe the answer for the first part of the problem

var numStore = (str.charAt(0) + str.charAt(1)) + str.charAt(2);
console.log(numStore);