London | 26-ITP-Sep | Mahir Shah | Sprint 3 | Sprint 3 Coursework

Sprint-3/1-key-errors/0.js

@@ -1,13 +1,22 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// the function has a parameter str, but then tries to make a new
+// variable also called str. so maybe cause error because str already exists
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
-function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
-  return str;
-}
+//function capitalise(str) {
+//  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+//  return str;
+//}
 
 // =============> write your explanation here
+// SyntaxError: Identifier 'str' has already been declared
+// Prediction was correct, str already exists
 // =============> write your new code here
+
+function capitalise(str) {
+  const capitaliseStr = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return capitaliseStr;
+}

Sprint-3/1-key-errors/1.js

@@ -2,19 +2,41 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+//decimalNumber already exists as a parameter, so const decimalNumber is making
+//a new variable with the same name. There is also a problem where decimalNumber is being
+//assigned 0.5, which won't cause errors, but means that no matter what is passed to the function
+//decimalNumber will always be 0.5
 
 // Try playing computer with the example to work out what is going on
 
-function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
-  const percentage = `${decimalNumber * 100}%`;
+//function convertToPercentage(decimalNumber) {
+//  const percentage = `${decimalNumber * 100}%`;
 
-  return percentage;
-}
+//  return percentage;
+//}
 
-console.log(decimalNumber);
+//convertToPercentage(0.6)
+//console.log(decimalNumber);
 
 // =============> write your explanation here
+//SyntaxError: Identifier 'decimalNumber' has already been declared
+//prediction correct, decimalNumber already exists so causes error. Removing the line
+//shows another error
+//console.log(decimalNumber);
+//            ^
+//ReferenceError: decimalNumber is not defined
+//This is because of scope, decimalNumber is defined in the function, so it only has scope
+//in the function
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+let decimalNumber = 0.6;
+console.log(decimalNumber);
+console.log(convertToPercentage(decimalNumber));

Sprint-3/1-key-errors/2.js

@@ -1,20 +1,26 @@
-
 // Predict and explain first BEFORE you run any code...
 
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+// In the function, 3 hasn't been assigned to num, so num is NaN and should return NaN.
+//Also when defining a function, the parameter should have the variable name, not a value
+//to pass in, unless you want to default value such as num = 3, which assigns 3 to num if
+// no value is passed in
 
-function square(3) {
-    return num * num;
-}
+//function square(3) {
+//    return num * num;
+//}
 
 // =============> write the error message here
-
+//SyntaxError: Unexpected number
 // =============> explain this error message here
-
+//syntaxError means there is a mistake in the way the code is written, so javascript can't
+// interpret the code. in this case there is a number here when there shouldn't be.
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
-
+function square(num) {
+  return num * num;
+}

Sprint-3/2-mandatory-debug/0.js

@@ -1,14 +1,25 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+//The multiply function doesn't return anything, only prints to console so the function call will have value undefined.
+//So when line 12 is executed, first it will print "The result of multiplying 10 and 32 is undefined"
+//Then on a new line it prints 320
 
-function multiply(a, b) {
-  console.log(a * b);
-}
+//function multiply(a, b) {
+//  console.log(a * b);
+//}
 
-console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+//console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
-
+//It first printed 320, then printed "The result of multiplying 10 and 32 is undefined" on the next line
+//I think this is because it goes through the line 12, executes the multiply function call first, then finishes the
+//console.log function call.
 // 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-3/2-mandatory-debug/1.js

@@ -1,13 +1,23 @@
 // Predict and explain first...
 //  =============> write your prediction here
+//when the return line is executed, the function exits. a + b is a separate line because it
+//is after the semicolon, so a + b is never reached and not returned. So line 11 will print
+//The The sum of 10 and 32 is undefined
 
-function sum(a, b) {
-  return;
-  a + b;
-}
+//function sum(a, b) {
+//  return;
+//  a + b;
+//}
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+//It did as predicted, for the reason I expected
 // 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-3/2-mandatory-debug/2.js

@@ -1,24 +1,41 @@
 // Predict and explain first...
-
 // Predict the output of the following code:
+//The last digit of 42 is 3
+//The last digit of 105 is 3
+//The last digit of 806 is 3
 // =============> Write your prediction here
+//num is defined outside of the function, so has scope in the function getLastDigit.
+//the function doesn't take any arguments and uses num, so will always return 3, no matter what
+//is passed to the function because it will use num, which is set to 103
 
-const num = 103;
+//const num = 103;
 
-function getLastDigit() {
-  return num.toString().slice(-1);
-}
+//function getLastDigit() {
+//  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)}`);
+//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
+// As I predicted, for the reason above
 // 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-3/3-mandatory-implement/1-bmi.js

@@ -16,4 +16,5 @@
 
 function calculateBMI(weight, height) {
   // return the BMI of someone based off their weight and height
+  return (weight / height ** 2).toFixed(1);
 }

Sprint-3/3-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(inputString) {
+  return inputString.toUpperCase().replaceAll(" ", "_");
+}

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

@@ -4,3 +4,28 @@
 // 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) {
+  const penceStringWithoutTrailingP = penceString.substring(
+    0,
+    penceString.length - 1,
+  );
+
+  const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+  const pounds = paddedPenceNumberString.substring(
+    0,
+    paddedPenceNumberString.length - 2,
+  );
+
+  const pence = paddedPenceNumberString
+    .substring(paddedPenceNumberString.length - 2)
+    .padEnd(2, "0");
+
+  return(`£${pounds}.${pence}`);
+}
+
+toPounds("10p");
+toPounds("100p");
+toPounds("232134p");
+toPounds("238p");
+toPounds("5234p");

Sprint-3/4-mandatory-interpret/time-format.js

@@ -22,17 +22,27 @@ function formatTimeDisplay(seconds) {
 
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
+// 3
 
 // 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 when it 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
+// 1. Last time it is called is pad(remainingSeconds). remainingSeconds = seconds % 60
+// with seconds = 61 this expression evaluates to 1, so when 1 is passed to pad, num is
+// assigned 1.
 
 // 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". Num is 1 which converted to the string "1" which is assigned to numString.
+// The while loop runs while numString length less than 2, and adds "0"
+// to the beginning string. So "1" becomes "01". the string length is now equal to two,
+// so the while loop exits and numString is returned with value "01"