sprint 2

Author: sofragiualina

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

@@ -1,5 +1,5 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> code will produce a SyntaxError the error will occur because the parameter str is being declared again with let str inside the function, which is not allowed
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
@@ -9,5 +9,10 @@ function capitalise(str) {
   return str;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+// =============> The error message says that str has already been declared this happens because str is already the function parameter,and the code tries to create another variable called str using let JavaScript does not allow a parameter and a let variable to have the same name in the same scope
+function capitalise(str) {
+  let capitalisedStr = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return capitalisedStr;
+}
+
+console.log(capitalise("hello"));

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

@@ -1,7 +1,7 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// =============> this program will produce a SyntaxError because decimalNumber is declared twice inside the function
 
 // Try playing computer with the example to work out what is going on
 
@@ -14,7 +14,13 @@ function convertToPercentage(decimalNumber) {
 
 console.log(decimalNumber);
 
-// =============> write your explanation here
+// =============> The error happens because decimalNumber is already a parameter of the function, so we cannot declare it again using const
 
 // 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(0.5));

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

@@ -3,18 +3,21 @@
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
+// =============> will cause a SyntaxError because function parameters must be variable names, not values like 3
 
 function square(3) {
     return num * num;
 }
 
-// =============> write the error message here
+// =============> SyntaxError: Unexpected number
 
-// =============> explain this error message here
+// =============> This error happens because 3 is not a valid parameter name in JavaScript function parameters must be variable names like num, not fixed values num is used inside the function but was never defined, so JavaScript throws an error
 
 // 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 +1,19 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// =============> will show undefined because the function does not return a value
 
 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
+// =============> the function only uses console.log() so it prints the result but does not return it when a function has no return, JavaScript returns undefined,which is why undefined appears in the final sentence
 
 // 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

@@ -1,5 +1,5 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> The sum of 10 and 32 is undefined because the function returns nothing
 
 function sum(a, b) {
   return;
@@ -8,6 +8,11 @@ function sum(a, b) {
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
+// =============> The problem is that the semicolon after return ends the function immediately. This means that a + b never runs, so the function returns undefined instead of the sum
 // 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

@@ -1,7 +1,7 @@
 // Predict and explain first...
 
 // Predict the output of the following code:
-// =============> Write your prediction here
+// =============> all three lines will output 3 as the last digit,even though the numbers are different
 
 const num = 103;
 
@@ -14,11 +14,21 @@ 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
+// =============>  The function does not use the numbers passed into it instead, it always uses the variable num which is set to 103. The last digit of 103 is 3, so the function always returns 3
 // Finally, correct the code to fix the problem
 // =============> write your new code here
 
+function getLastDigit(num) {
+  return num.toString().slice(-1);
+}
+
+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

Sprint-2/3-mandatory-implement/1-bmi.js

@@ -15,5 +15,6 @@
 // It should return their Body Mass Index to 1 decimal place
 
 function calculateBMI(weight, height) {
-    // return the BMI of someone based off their weight and height
-}
+  return (weight / (height * height)).toFixed(1);
+  // return the BMI of someone based off their weight and height
+}

Sprint-2/3-mandatory-implement/2-cases.js

@@ -14,3 +14,6 @@
 // You will need to come up with an appropriate name for the function
 // Use the MDN string documentation to help you find a solution
 // This might help https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
+function toUpperSnakeCase(str) {
+  return str.toUpperCase().replaceAll(" ", "_");
+}

Sprint-2/3-mandatory-implement/3-to-pounds.js

@@ -4,3 +4,33 @@
 // You will need to declare a function called toPounds with an appropriately named parameter.
 
 // You should call this function a number of times to check it works for different inputs
+function toPounds(penceString) {
+  // takes the p from the end of the string
+  const penceStringWithoutTrailingP = penceString.substring(
+    0,
+    penceString.length - 1
+  );
+
+  // the number must have at least 3 digits
+  // 8 becomes 008
+  const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+
+  // Get everything except the last 2 digits for pounds
+  const pounds = paddedPenceNumberString.substring(
+    0,
+    paddedPenceNumberString.length - 2
+  );
+
+  // Get the last 2 digits for pence
+  const pence = paddedPenceNumberString
+    .substring(paddedPenceNumberString.length - 2)
+    .padEnd(2, "0");
+
+  // Return the result in pounds format
+  return `£${pounds}.${pence}`;
+}
+
+console.log(toPounds("399p")); // £3.99
+console.log(toPounds("45p")); // £0.45
+console.log(toPounds("8p")); // £0.08
+console.log(toPounds("1234p")); // £12.34

Sprint-2/4-mandatory-interpret/time-format.js

@@ -21,18 +21,18 @@ function formatTimeDisplay(seconds) {
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// =============> 3 times hours minutes and seconds
 
 // Call formatTimeDisplay with an input of 61, now answer the following:
 
 // b) What is the value assigned to num when pad is called for the first time?
-// =============> write your answer here
+// =============> 0
 
 // c) What is the return value of pad is called for the first time?
-// =============> write your answer here
+// =============> 00
 
 // d) What is the value assigned to num when pad is called for the last time in this program?  Explain your answer
-// =============> write your answer here
+// =============> The remaining seconds are calculated using % 60, so when the input is 61, the result is 1 second left over
 
 // e) What is the return value of pad when it is called for the last time in this program?  Explain your answer
-// =============> write your answer here
+// =============> 01 function adds a leading zero to any number that is less than 10 and time will be in two digits