If have a question on the recursive functions.IN one of the examples the is. a line
return find(current + 5, (${history} + 5)) ||
What does the `(${history} do ? it really makes it hard when they describe a function but we have not learned what certain Javascript parameters actually do and how they work.
// Minimum
function min(a,b){
if (a < b){
return a;
}
else{
return b;
}
}
console.log(min(2,1));
// Recursion
function isEven(a){
if(a < 0){
return "The number must be greater than zero";
}
if(a == 0){
return true;
}
if(a == 1){
return false;
}
else{
return isEven(a - 2);
}
}
console.log(isEven(50));
console.log(isEven(75));
console.log(isEven(-1));
// Bean Counting
function countBs(string, lookingFor = "B") {
let found = 0;
for (let n = 0; n < string.length ; n++){
if(string[n] == lookingFor) {
found++;
}
}
return found;
}
console.log(countBs("BBCSBfaB"));
1. Excercise 1 - Minimum
function min (x,y){
if (x < y){
alert(x)
}
else if (x > y){
alert(y)
}
}
min (11, 10);
Excersice 2 - Recursion
function isEven(a){
if(a < 0){
alert (“Please no Negative numbers, thanks!”);
}
else if (a == 0) {
alert (“true”);
}else if (a == 1){
alert (“false”);
}else{
return isEven(a - 2);
}
}isEven(8)
Excersice 3 - Beans
minimum
function min(a,b){
if(a<b) return a;
else return b;}
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);}
bean counting
function countBs(string){
let count=0;
for(let i=0; i<string.length; i++){
if(string[i]==“B”){
count+=1;
}
}
}
function countChar(string, char){
let count=0;
for(let i=0; i<string.length; i++){
if(string[i]== char){
count +=1;
}
}
return counted;
}
function countBs(string){
return countchar(string, “B”);
}
Hi, thanks so much for your assistance with the dynamic fruitlist assignment but after making the correction it still won’t run on my computer meanwhile it ran successfully on yours. I have actually been stuck ever since and tried to unstuck myself to no avail. Please I still need help!!! Thanks
Please share the updated code as well.
Thanks.
A.Malik
1. Minimum
function printMin (x, y) {
if (x < y) {
return (x);
}else {
return (y);
}
}
printMin (12, 33));
//→ returns 12
2. Recursion
function isEven (n) {
if (n === 0) {
return true;
}
if (n === 1) {
return false;
}
return isEven(n-2);
}
isEven(50);
//→ returns true
3. Bean Counting
function countBs (string) {
let result = 0;
for ( let i = 0; i <= string.length; i += 1) {
if (string.charAt(i) === 'B')
result += 1;
}
return result;
}
countBs("BigBootyB....es");
// → returns 3
function minNumber(arg1, arg2) {
document.write(Math.min(arg1, arg2));
}
minNumber(400, 300);
Alternative Without Using Math.min
function minimumNumber(args1, args2) {
if (args1>args2) {
return (args2);
} else if (args1<args2) {
return args1;
} else {
return "These are Equal!";
}
}
document.write(minimumNumber(1, 3));
function isEven(num) {
if (num == 0) {
return "Number is Even";
} else if (num == 1) {
return "Number is Odd";
} else {
return isEven(num - 2);
}
}
document.write(isEven(50));
document.write(isEven(75));
Fix for a Negative Number
function isEven(num) {
// These two lines below have been included to firstly negate a negative number
if (num < 0) {
return isEven(num * -1);
// ... And then continue as per before:
} else if (num == 0) {
return "Number is Even";
} else if (num == 1) {
return "Number is Odd";
} else {
return isEven(num - 2);
}
}
document.write(isEven(-1));
function countBS(string) {
var letterB = 0;
for (var j = 0; j < string.length; j++) {
if (string[j] == "B") {
letterB = letterB + 1;
}
}
return letterB;
}
document.write(countBS("Babies")); // Prints "1"
document.write(countBS("BaBies")); // Prints "2"
document.write(countBS("Hello")); // Prints "0"
countChar Alternative
function countChar(newString, character) {
var letterNum = 0;
for (var k = 0; k < newString.length; k++) {
if (newString[k] == character) {
letterNum = letterNum + 1;
}
}
return letterNum;
}
document.write(countChar("Plebs", "P")); // Prints "1"
document.write(countChar("plebs", "P")); // Prints "0"
document.write(countChar("PerPhekt", "P")); // Prints "2"
Hi, Could someone please help me to understand this: (pg 48)
If you write an = operator after a parameter, followed by an expression, the
value of that expression will replace the argument when it is not given.
For example, this version of power makes its second argument optional. If
you don’t provide it or pass the value undefined, it will default to two, and the
function will behave like square.
function power(base, exponent = 2) {
let result = 1;
for (let count = 0; count < exponent; count++) {
result *= base;
}
return result;
}
console.log(power(4));
// → 16
console.log(power(2, 6));
// → 64
I understood the 1st argument = 16
But not the 2nd one. Why is it 64?
And this 1 (pg 50)
function power(base, exponent) {
if (exponent == 0) {
return 1;
} else {
return base * power(base, exponent - 1);
}
}
console.log(power(2, 3));
// → 8
How it’s = 8?
Thanks,
// IsEven
function IsEven(n) {
if (n < 0) n = -n;
if (n == 0) return 1;
else if (n == 1) return 0;
else return IsEven(n-2);
}
// counting character functions...
function countBs(s) {
count = 0;
for (var i = 0; i < s.length; i++) count += (s[i] == 'B');
return count;
}
function countchar(s,c) {
count = 0;
for (var i = 0; i < s.length; i++) count += (s[i] == c);
return count;
}
What are we supposed to do for the minimum excercise??
Recursion exercise:
function isEven(number){
if (number % 2 == 0){
return(“true”)
}
else{
return(“false”)
}
}
console.log(isEven(50))
console.log(isEven(75))
console.log(isEven(-1))
.
Minimum
function mn(a, b) {
return a>b ? b : a;
}
Recursion
function isEven(num) {
if(num <0){return isEven(-num);}
if(num ==0){return true;}
if(num ==1){return false;}
return isEven(num-2);
}
Bean Counting
function countChar(word, chr){
if(chr.length>1){
return 0;
}
let counter =0;
for(let i=0;i<word.length;i++){
if(word[i]==chr){
counter++
}
}
return counter;
}
Min:
let a = window.prompt(“Ïnsira o primeiro numero”);
let b = window.prompt(“Insira o segundo numero”);
function min (a, b)
{
if (a>b);
console.log(b)
}
if (a<b);
{
console.log(a)
}
function isEven(n)
{
if (n %2 == 0)
{
return true;
}
if (n %2 == 1)
{
return false;
}
if (n < 0)
{
return isEven(-n);
}
else
{
return isEven(n - 2);
}
}
console.log(isEven(75));
// false
console.log(isEven(50));
// true
console.log(isEven(-1)):
// false
function countBs(myString)
{
return countChar(myString, ‘B’);
}
function countChar(myString, character)
{
let count = 0;
while (myString.length > 0)
{
if (myString.charAt(0) == character) count++;
myString = myString.substr(1);
}
return count;
}
console.log(countBs("Baby blues, Bubba gun, boom Boom!"));Minimum:
function min(a,b) {
if (a < b){
return a;
}else{
return b;
}
}
console.log(min(4234,46));
Recursion:
//var even = "The number is even";
//var odd = "The number is odd";
var evenNum = 0;
var oddNum = 1;
function isEven(number) {
if(number == evenNum) {
return true;
//console.log(even);
}else if(number == oddNum) {
return false;
//console.log(odd);
}else if(number < 0){
return isEven(-number);
}else{
number -= 2;
return isEven(number);
}
}
console.log(isEven(50));
console.log(isEven(75));
console.log(isEven(-1));
Bean Counting:
function countBs(anyWord){
return countChar(anyWord, "B");
}
console.log(countBs("BBC"));
function countChar(anyWord, letter) {
var letterAmount = 0;
for (var position = 0; position < anyWord.length; position++){
if(anyWord[position] == letter) {
letterAmount++;
}
}
return letterAmount;
}
console.log(countChar("kakkerlak", "k"));
// Minimum
// 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(50));
console.log(isEven(75));
console.log(isEven(-1));
// Bean counting
Part 1:
function countBs(string) {
let result = 0;
for (let i = 0; i <= string.length; i++) {
if (string[i] === ‘B’) {
result = result + 1;
}
}
return result;
]
Part 2:
function countChar(string, character) {
let result = 0;
for (let i = 0; i <= string.length; i++) {
if (string[i] === character) {
result = result + 1;
}
}
return result;
}
Part 3:
function countBs(string) {
return countChar(string, ‘B’);
}
function countChar(string, character) {
let result = 0;
for (let i = 0; i <= string.length; i++) {
if (string[i] === character) {
result = result + 1;
}
}
return result;
}
Minimum
function min(a,b){
if (a<b) console.log (a);
else (console.log(b));
}
Recursion
function isEven(n){
if (n==0) return true;
else if (n==1) return false;
else if (n<0) return isEven(-n)
return isEven(n-2);
}
function countBs(string){
let count=0;
for (let a=0; a<string.length; a++){
if (string[a]==“B”){
count +=1;
}
}
return count;
}
function countChar(char, string){
let count=0;
for (let a=0; a<string.length; a++){
if (string[a]==char){
count +=1;
}
}
return count;
}MINIMUM
function min (a, b){
if (a < b) {
return a;
}
else {
return b;
}
}
min(7 ,1)
RECURSION
// Define a recursive function isEven
function isEven(n) {
// what if n is negative. I did not really get this part. How does this solve the problem??
if (n < 0) {
n = -n
}
// Zero is even. (Return boolean)
if (n === 0) {
return true;
}
// One is odd. (Return boolean)
if (n === 1) {
return false;
}
// If n is not (0 || 1), subtract 2 from n until it is equal to 0 or 1
return isEven(n - 2);
};
console.log(isEven(6))
// true
console.log(isEven(5))
// false
// if n == negative there is no way of subtracting to reach 0 || 1
// BEAN COUNTING
// function has a (string) as its only argument
function countBs(input) {
// create a result, set to 0 (will be returned at the end)
let result = 0;
//loop over the string
for (let i = 0; i < input.length; i++) {
//if current character is a "B"
if (input[i] === "B") {
// increment our result by 1
result++;
}
}
// return result
return result;
};
//return result
return result;
}
function countChar(string, character) {
let result = 0;
//loop over the string
for (let i = 0; i < string.length; i++) {
//if current character is a "B"
if (string[i] === character) {
// increment our result by 1
result++;
}
}
// return result
return result;
};
I received the instructions (thanks Malik) and I post them here in case it will help someone:
console.log(power(4));
Here, the base is 4 and the exponent is 2 (by default since nothing passed). Therefore, the result would be 4 * 4 which is equal to 16.
console.log(power(2, 6));
Here, the base is 2 and the exponent is 6 (by passing an explicit value and disregarding default). Therefore, the result would be 2 *2 *2 *2 *2 *2 which is equal to 64.
The second question -
console.log(power(2, 3));
Here, we are using recursions instead of a normal for-loop to multiply the numbers. So, for every recursion, the base keeps getting multiplied. Therefore, the answer would look like this –
Step 1 - 2 * power(2,2)
Step 2- 2 * 2 * power(2, 1)
Step 3 - 2 * 2 * 2 * power (2, 0)
step 4 - 2 * 2 * 2 * 1 [which equals 8]