From 6818ea51ab818cb850a72e5298c447cc7d1748d3 Mon Sep 17 00:00:00 2001 From: KhotKeys Date: Sat, 4 Jul 2026 15:13:42 +0100 Subject: [PATCH] Complete task for the Sprint-1 --- Sprint-1/1-key-exercises/1-count.js | 3 ++- Sprint-1/1-key-exercises/2-initials.js | 2 +- Sprint-1/1-key-exercises/3-paths.js | 4 ++-- Sprint-1/1-key-exercises/4-random.js | 14 ++++++++--- Sprint-1/2-mandatory-errors/0.js | 5 ++-- Sprint-1/2-mandatory-errors/1.js | 4 +++- Sprint-1/2-mandatory-errors/2.js | 5 ++-- Sprint-1/2-mandatory-errors/3.js | 12 +++++----- Sprint-1/2-mandatory-errors/4.js | 9 ++++++-- .../1-percentage-change.js | 20 +++++++++------- .../3-mandatory-interpret/2-time-format.js | 23 +++++++++++-------- Sprint-1/3-mandatory-interpret/3-to-pounds.js | 18 +++++++++------ 12 files changed, 75 insertions(+), 44 deletions(-) diff --git a/Sprint-1/1-key-exercises/1-count.js b/Sprint-1/1-key-exercises/1-count.js index 117bcb2b6e..6c105794eb 100644 --- a/Sprint-1/1-key-exercises/1-count.js +++ b/Sprint-1/1-key-exercises/1-count.js @@ -3,4 +3,5 @@ let count = 0; count = count + 1; // Line 1 is a variable declaration, creating the count variable with an initial value of 0 -// Describe what line 3 is doing, in particular focus on what = is doing +// Line 3 is a variable reassignment. The = (assignment operator) takes the result of count + 1 +// (which evaluates to 1) and stores it back into the existing count variable, replacing the old value. diff --git a/Sprint-1/1-key-exercises/2-initials.js b/Sprint-1/1-key-exercises/2-initials.js index 47561f6175..4a09edec56 100644 --- a/Sprint-1/1-key-exercises/2-initials.js +++ b/Sprint-1/1-key-exercises/2-initials.js @@ -5,7 +5,7 @@ let lastName = "Johnson"; // Declare a variable called initials that stores the first character of each string. // This should produce the string "CKJ", but you must not write the characters C, K, or J in the code of your solution. -let initials = ``; +let initials = `${firstName[0]}${middleName[0]}${lastName[0]}`; // https://www.google.com/search?q=get+first+character+of+string+mdn diff --git a/Sprint-1/1-key-exercises/3-paths.js b/Sprint-1/1-key-exercises/3-paths.js index ab90ebb28e..98ab371c3f 100644 --- a/Sprint-1/1-key-exercises/3-paths.js +++ b/Sprint-1/1-key-exercises/3-paths.js @@ -17,7 +17,7 @@ console.log(`The base part of ${filePath} is ${base}`); // Create a variable to store the dir part of the filePath variable // Create a variable to store the ext part of the variable -const dir = ; -const ext = ; +const dir = filePath.slice(0, lastSlashIndex); +const ext = base.slice(base.lastIndexOf(".")); // https://www.google.com/search?q=slice+mdn \ No newline at end of file diff --git a/Sprint-1/1-key-exercises/4-random.js b/Sprint-1/1-key-exercises/4-random.js index 292f83aabb..a3de7bcf84 100644 --- a/Sprint-1/1-key-exercises/4-random.js +++ b/Sprint-1/1-key-exercises/4-random.js @@ -3,7 +3,15 @@ const maximum = 100; const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum; +console.log(num); + // In this exercise, you will need to work out what num represents? -// Try breaking down the expression and using documentation to explain what it means -// It will help to think about the order in which expressions are evaluated -// Try logging the value of num and running the program several times to build an idea of what the program is doing +// num represents a random integer between 1 and 100 (inclusive). +// +// Breakdown: +// 1. Math.random() generates a random decimal in [0, 1) +// 2. (maximum - minimum + 1) = 100, so Math.random() * 100 gives a decimal in [0, 100) +// 3. Math.floor(...) rounds down to an integer in [0, 99] +// 4. Adding minimum (1) shifts the range to [1, 100] +// +// So num is a random whole number from 1 to 100. diff --git a/Sprint-1/2-mandatory-errors/0.js b/Sprint-1/2-mandatory-errors/0.js index cf6c5039f7..1ae934d04b 100644 --- a/Sprint-1/2-mandatory-errors/0.js +++ b/Sprint-1/2-mandatory-errors/0.js @@ -1,2 +1,3 @@ -This is just an instruction for the first activity - but it is just for human consumption -We don't want the computer to run these 2 lines - how can we solve this problem? \ No newline at end of file +// This is just an instruction for the first activity - but it is just for human consumption +// We don't want the computer to run these 2 lines - how can we solve this problem? +// Solution: Prefix each line with // to make them comments, as done here. \ No newline at end of file diff --git a/Sprint-1/2-mandatory-errors/1.js b/Sprint-1/2-mandatory-errors/1.js index 7a43cbea76..f1318d2089 100644 --- a/Sprint-1/2-mandatory-errors/1.js +++ b/Sprint-1/2-mandatory-errors/1.js @@ -1,4 +1,6 @@ // trying to create an age variable and then reassign the value by 1 +// Error: Assignment to constant variable. +// const variables cannot be reassigned. Fix: use let instead. -const age = 33; +let age = 33; age = age + 1; diff --git a/Sprint-1/2-mandatory-errors/2.js b/Sprint-1/2-mandatory-errors/2.js index e09b89831d..485338158f 100644 --- a/Sprint-1/2-mandatory-errors/2.js +++ b/Sprint-1/2-mandatory-errors/2.js @@ -1,5 +1,6 @@ // Currently trying to print the string "I was born in Bolton" but it isn't working... -// what's the error ? +// Error: ReferenceError - cityOfBirth is used before it is declared. +// const is not hoisted like var. Fix: declare the variable before using it. -console.log(`I was born in ${cityOfBirth}`); const cityOfBirth = "Bolton"; +console.log(`I was born in ${cityOfBirth}`); diff --git a/Sprint-1/2-mandatory-errors/3.js b/Sprint-1/2-mandatory-errors/3.js index ec101884db..a3910d0985 100644 --- a/Sprint-1/2-mandatory-errors/3.js +++ b/Sprint-1/2-mandatory-errors/3.js @@ -1,9 +1,9 @@ +// Prediction: .slice() is a string method, not a number method, so it will throw a TypeError. +// Error: TypeError: cardNumber.slice is not a function +// Fix: convert the number to a string first. + const cardNumber = 4533787178994213; -const last4Digits = cardNumber.slice(-4); +const last4Digits = cardNumber.toString().slice(-4); +console.log(last4Digits); // The last4Digits variable should store the last 4 digits of cardNumber -// However, the code isn't working -// Before running the code, make and explain a prediction about why the code won't work -// Then run the code and see what error it gives. -// Consider: Why does it give this error? Is this what I predicted? If not, what's different? -// Then try updating the expression last4Digits is assigned to, in order to get the correct value diff --git a/Sprint-1/2-mandatory-errors/4.js b/Sprint-1/2-mandatory-errors/4.js index 5f86c730bc..7bbe15e213 100644 --- a/Sprint-1/2-mandatory-errors/4.js +++ b/Sprint-1/2-mandatory-errors/4.js @@ -1,2 +1,7 @@ -const 12HourClockTime = "8:53pm"; -const 24hourClockTime = "20:53"; +// Error: variable names cannot start with a digit. +// Fix: rename the variables to valid identifiers. +const twelveHourClockTime = "8:53pm"; +const twentyFourHourClockTime = "20:53"; + +console.log(twentyFourHourClockTime); +console.log(twelveHourClockTime); diff --git a/Sprint-1/3-mandatory-interpret/1-percentage-change.js b/Sprint-1/3-mandatory-interpret/1-percentage-change.js index e24ecb8e18..311960b4e1 100644 --- a/Sprint-1/3-mandatory-interpret/1-percentage-change.js +++ b/Sprint-1/3-mandatory-interpret/1-percentage-change.js @@ -2,21 +2,25 @@ let carPrice = "10,000"; let priceAfterOneYear = "8,543"; carPrice = Number(carPrice.replaceAll(",", "")); -priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," "")); +priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", "")); const priceDifference = carPrice - priceAfterOneYear; const percentageChange = (priceDifference / carPrice) * 100; console.log(`The percentage change is ${percentageChange}`); -// Read the code and then answer the questions below +// a) Function calls: +// Line 4: replaceAll(",", "") and Number(...) +// Line 5: replaceAll(",", "") and Number(...) +// Line 10: console.log(...) -// a) How many function calls are there in this file? Write down all the lines where a function call is made +// b) The error on line 5 is a missing comma between the two arguments to replaceAll: +// replaceAll("," "") should be replaceAll(",", ""). Fixed above. -// b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem? +// c) Variable reassignment statements: lines 4 and 5 (carPrice = ..., priceAfterOneYear = ...) -// c) Identify all the lines that are variable reassignment statements +// d) Variable declarations: lines 1, 2 (let), lines 7, 8 (const) -// d) Identify all the lines that are variable declarations - -// e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression? +// e) Number(carPrice.replaceAll(",","")) first removes all commas from the string "10,000" +// turning it into "10000", then converts that string into the number 10000. +// This is necessary because you cannot do arithmetic on strings. diff --git a/Sprint-1/3-mandatory-interpret/2-time-format.js b/Sprint-1/3-mandatory-interpret/2-time-format.js index 47d2395587..fbd809a8f7 100644 --- a/Sprint-1/3-mandatory-interpret/2-time-format.js +++ b/Sprint-1/3-mandatory-interpret/2-time-format.js @@ -9,17 +9,22 @@ const totalHours = (totalMinutes - remainingMinutes) / 60; const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`; console.log(result); -// For the piece of code above, read the code and then answer the following questions +// a) There are 6 variable declarations: movieLength, remainingSeconds, totalMinutes, +// remainingMinutes, totalHours, result. -// a) How many variable declarations are there in this program? +// b) There is 1 function call: console.log(result) on line 10. -// b) How many function calls are there? +// c) movieLength % 60 uses the modulo (remainder) operator. +// It gives the remainder after dividing movieLength by 60, i.e. the leftover seconds +// that don't make a full minute. -// c) Using documentation, explain what the expression movieLength % 60 represents -// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators +// d) totalMinutes = (movieLength - remainingSeconds) / 60 +// First, the remaining seconds are subtracted so the value is an exact multiple of 60. +// Dividing by 60 then converts the total seconds into whole minutes. -// d) Interpret line 4, what does the expression assigned to totalMinutes mean? +// e) result represents the movie length formatted as HH:MM:SS (hours:minutes:seconds). +// A clearer name would be formattedDuration or timeDisplay. -// e) What do you think the variable result represents? Can you think of a better name for this variable? - -// f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer +// f) The code works for any non-negative integer value of movieLength. +// It will not work correctly for negative values (a negative duration makes no sense) +// but for any valid seconds value >= 0 the arithmetic is correct. diff --git a/Sprint-1/3-mandatory-interpret/3-to-pounds.js b/Sprint-1/3-mandatory-interpret/3-to-pounds.js index 60c9ace69a..9e9677ba57 100644 --- a/Sprint-1/3-mandatory-interpret/3-to-pounds.js +++ b/Sprint-1/3-mandatory-interpret/3-to-pounds.js @@ -17,11 +17,15 @@ const pence = paddedPenceNumberString console.log(`£${pounds}.${pence}`); -// This program takes a string representing a price in pence -// The program then builds up a string representing the price in pounds - -// You need to do a step-by-step breakdown of each line in this program -// Try and describe the purpose / rationale behind each step - -// To begin, we can start with +// Step-by-step breakdown: // 1. const penceString = "399p": initialises a string variable with the value "399p" +// 2. penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1) +// Removes the trailing "p", leaving "399" +// 3. paddedPenceNumberString = "399".padStart(3, "0") +// Ensures the string is at least 3 characters long by padding with "0" on the left. +// "399" is already 3 chars so it stays "399". For "9p" this would give "009". +// 4. pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2) +// Takes all characters except the last 2. For "399" this gives "3" (the pounds part). +// 5. pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0") +// Takes the last 2 characters ("99") as the pence part, and pads to 2 chars if needed. +// 6. console.log(`£${pounds}.${pence}`): prints "£3.99"