Finish section 1 and 2 for sprint 2 course work.

Author: Jacknguyen4438

Sprint-2/1-key-errors/0.js

@@ -1,13 +1,29 @@
 // Predict and explain first...
 //  =============> write your prediction here
 
+/*
+My prediction is that this function will take the first letter of a string and capital it.
+*/
+
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
-function capitalise(str) {
+/*function capitalise(str) {
   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
-}
+}*/
 
 // =============> write your explanation here
+
+/*
+The main reason why the capitalise function have a not define error because the the str variable have been declare in the parameter
+inside the function, the str variable is re-declare again that will break the rule of how variable work.
+*/
+
 // =============> write your new code here
+
+function capitalise(str) {
+  let firstCapitaLetter = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return firstCapitaLetter;
+};
+console.log(capitalise("hello"));

Sprint-2/1-key-errors/1.js

@@ -2,9 +2,10 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// When the JS executed the code, it will give 2 possible error 1 is decimalNumber is define inside the function and decimalNumber is undefined when using console.log
 
 // Try playing computer with the example to work out what is going on
-
+/*
 function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
@@ -13,8 +14,26 @@ function convertToPercentage(decimalNumber) {
 }
 
 console.log(decimalNumber);
-
+*/
 // =============> write your explanation here
 
+/*
+For function convertToPercentage there are 1 error:
+  inside the function the decimalNumber parameter is being re-declare and given a fix value, this will give this function a 
+  decimalNumber are ready defined.
+
+Next is when we console.log the function instead of calling the function name and value we used the function parameter variable name
+instead. This will give the error decimalNumber is undefined.
+*/
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+console.log(convertToPercentage(0.25));

Sprint-2/1-key-errors/2.js

@@ -5,16 +5,23 @@
 
 // =============> write your prediction of the error here
 
+// For function square the variable inside the parameter will have a error, because number cant be used when name a variable and num variable is undefine.
+/*
 function square(3) {
     return num * num;
 }
-
+*/
 // =============> write the error message here
+// SyntaxError: Unexpected number
 
 // =============> explain this error message here
+//Because number cant be used when name a variable.
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
-
+function square(num) {
+    return num * num; 
+};
+console.log(square(3));

Sprint-2/2-mandatory-debug/0.js

@@ -1,14 +1,32 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+/*
+The function multiply when is log into the terminal. we will receive a print out expression from 
+first console.log inside the function and undefined value from the string template inside the section console.log.
+*/
 
+/*
 function multiply(a, b) {
   console.log(a * b);
 }
 
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+*/
 
 // =============> write your explanation here
+/*
+First the function multiply have 2 parameter identifier a and b, the main purpose of this function is to multiply any argument that put 
+into the identifier a and b. Inside the the function is we have the function call console.log and nested inside is the expression from multiply of a and b.
+However this will lead to error, since we need to return the expression(value) back to the function so it can be re used when call in a string template or other
+function.
 
+*/
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+
+function multiply(a, b) {
+  return a * b;
+}
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);

Sprint-2/2-mandatory-debug/1.js

@@ -1,13 +1,27 @@
 // Predict and explain first...
 //  =============> write your prediction here
-
+// The function sum when is call inside the string template. The print out will be "The sum of 10 and 32 is undefined".
+/*
 function sum(a, b) {
   return;
   a + b;
 }
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
-
+*/
 // =============> write your explanation here
+
+/*
+For the function sum the writing format is correct but however instead of return the expression from the combine value 
+of a and b, right now there is no expression return back to the function. So when the function is used inside the string template, 
+it give the value of undefined instead of actual  value of a and b combine together.
+*/
+
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+
+function sum(a, b) {
+  return a + b;
+}
+
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);

Sprint-2/2-mandatory-debug/2.js

@@ -3,6 +3,11 @@
 // Predict the output of the following code:
 // =============> Write your prediction here
 
+/* The function getLastDigit should get the last digit number from any number argument pass into the function, but however it only take 
+value from variable num and only give out the value of 3.
+*/
+
+/*
 const num = 103;
 
 function getLastDigit() {
@@ -12,13 +17,35 @@ function getLastDigit() {
 console.log(`The last digit of 42 is ${getLastDigit(42)}`);
 console.log(`The last digit of 105 is ${getLastDigit(105)}`);
 console.log(`The last digit of 806 is ${getLastDigit(806)}`);
-
+*/
 // Now run the code and compare the output to your prediction
 // =============> write the output here
+/*
+The last digit of 42 is 3
+The last digit of 105 is 3
+The last digit of 806 is 3
+*
+/
+
 // Explain why the output is the way it is
 // =============> write your explanation here
+/* 
+Because the function getLastDigit when use, instead of picking last digit number of any random number argument pass into the function
+it only pick last digit number from the variable num value of 103. So when the user try to input other random number into 
+the function is only print out the number 3 as the result.
+*/
 // Finally, correct the code to fix the problem
 // =============> write your new code here
 
+const num = 103;
+
+function getLastDigit(digit) {
+  return digit.toString().slice(-1);
+}
+console.log(`The last digit of 103 is ${getLastDigit(num)}`);
+console.log(`The last digit of 42 is ${getLastDigit(42)}`);
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);
+
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem