latest part 3

Author: Arthur

Sprint-1/3-mandatory-interpret/1-percentage-change.js

@@ -2,7 +2,7 @@ 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;
@@ -12,11 +12,30 @@ console.log(`The percentage change is ${percentageChange}`);
 // Read the code and then answer the questions below
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
+6 
 
 // 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?
+It lacks comma insides the replaceAll.
 
-// c) Identify all the lines that are variable reassignment statements
 
+// c) Identify all the lines that are variable reassignment statements
+carPrice = Number(carPrice.replaceAll(",", ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 // d) Identify all the lines that are variable declarations
+let carPrice = "10,000";
+let priceAfterOneYear = "8,543";
+
+const priceDifference = carPrice - priceAfterOneYear;
+const percentageChange = (priceDifference / carPrice) * 100;
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+It is to take out the comma insides the number of carPrice.
+
+
+
+
+
+
+
+
+

Sprint-1/3-mandatory-interpret/2-time-format.js

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 6; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -12,14 +12,21 @@ console.log(result);
 // For the piece of code above, read the code and then answer the following questions
 
 // a) How many variable declarations are there in this program?
-
+//6
 // b) How many function calls are there?
-
+//1
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
 
+//It divides totalMinutes into 60, see how much remainingMinutes left.
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+//After deducting the totalMinutes, and divide the second. How much do he have the totalMinutes ?
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+//The total duration of the movieLength.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+//for one hour = 3600 minutes .  1:00:00
+//for 59 minutes =  3540 minutes .  0:59:0
+//for seconds =  6 seconds .  0:0:6

Sprint-1/3-mandatory-interpret/3-to-pounds.js

@@ -24,4 +24,32 @@ console.log(`£${pounds}.${pence}`);
 // Try and describe the purpose / rationale behind each step
 
 // To begin, we can start with
-// 1. const penceString = "399p": initialises a string variable with the value "399p"
+1. const penceString = "399p": initialises a string variable with the value "399p"
+2.
+const penceStringWithoutTrailingP = penceString.substring(
+  0,
+  penceString.length - 1
+);  the purpose of this is to take out the p.
+
+
+3.
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+if it is shorter than 3 characters, the 0 will add in front of the number  ;  but 399 is already 3 numbers so we donot need to do anything.
+
+
+
+4. const pounds = paddedPenceNumberString.substring(
+  0,
+  paddedPenceNumberString.length - 2
+);  the length of the string is 3 , after -2 , it will become 1. The const pounds will take out 3 and it will become 3.
+
+
+5. const pence = paddedPenceNumberString
+  .substring(paddedPenceNumberString.length - 2)
+  .padEnd(2, "0");
+
+  It will take out the number from the end to 1 ; so it will have 99. 
+
+6.console.log(`£${pounds}.${pence}`);  
+
+Finally it will put the pounds and the pence into the template and print it out. The result will be £${3}.${99} ;