London | 25-ITP-Jan | Kayanat Suleman | Sprint 2 | Structuring and Testing Data

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

@@ -1,5 +1,7 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// I predict that the code will throw an error due to the fact that the function redeclares the
+// the str using let str. This is not allowed as it is already defined as a parameter. 
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
@@ -9,5 +11,15 @@ function capitalise(str) {
   return str;
 }
 
-// =============> write your explanation here
+//console.log(capitalise("hello"));
+// =============> write your explanation here 
+// The error occures due to the fact that str is already declared as a function parameter.
+// Using let str inside the function tries to redeclare the same variable, which is causing a syntaxError for Javascript.
+
+// =============> write your new code here
 // =============> write your new code here
+function capitalise(str) {
+  return `${str[0].toUpperCase()}${str.slice(1)}`;
+}
+
+console.log(capitalise("hello"));

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

@@ -2,6 +2,9 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// My prediction is that this will solution will fail due to the fact that the decimalNumber is being declared twice.
+// The second issue is the decimalNumber is being logged to the console, but this is parameter for convertToPercentage.
+// So to call the function accurately we need to call convertToPercentage not decimalNumber.
 
 // Try playing computer with the example to work out what is going on
 
@@ -15,6 +18,14 @@ function convertToPercentage(decimalNumber) {
 console.log(decimalNumber);
 
 // =============> write your explanation here
+// The function convertToPercentage takes a decimal number as parameter.
+// It multiplies the number by 100 and converts it into a string with a "%" symbol.
+// The corrected version removes the duplicate declaration and calls the function properly.
 
 // 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

@@ -4,17 +4,34 @@
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+// This function will cause a syntax error due to the fact that the parameter should be variable name, not a literal value.
+// The second issue is that "num" is used inside the function however it is not defined anywhere.
 
 function square(3) {
     return num * num;
 }
 
 // =============> write the error message here
+// SyntaxError: Unexpected number
+//   at internalCompileFunction (node:internal/vm:76:18)
+//   at wrapSafe (node:internal/modules/cjs/loader:1283:20)
+//   at Module._compile (node:internal/modules/cjs/loader:1328:27)
+//   at Module._extensions..js (node:internal/modules/cjs/loader:1422:10)
+//   at Module.load (node:internal/modules/cjs/loader:1203:32)
+//  at Module._load (node:internal/modules/cjs/loader:1019:12)
+//   at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:128:12)
+//  at node:internal/main/run_main_module:28:49
 
 // =============> explain this error message here
+// This error message means that JS expects a parameter name within the function.
+// The second error message is "num" is not declared.
 
 // 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 +1,22 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+// The function multiply(a, b) logs the result within the function but does not return anything.
 
 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
+// Console.log() will print something.
+// Return gives a value back to the caller - the function currently will print the result but does not return it. 
 
 // 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 +1,24 @@
-// Predict and explain first...
-//  =============> write your prediction here
+  // Predict and explain first...
+  //  =============> write your prediction here
+  // I predict that the function will not return undefined.
+  // This is due to the fact that the return statement is on its own line, therefore trying to do the addition will not work as the code is not read.
 
-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)}`);
+    console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
-// Finally, correct the code to fix the problem
-//  =============> write your new code here
+  // =============> write your explanation here
+  // The return statement is written on its own line, therefore JS automatically inserts a semicolon after the return.
+  // This means that the function exits immediately and returns undefined.
+  // The expression a + b; is not executed.
+
+  // 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

@@ -2,23 +2,41 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+// I predict that the three console.log messages will always output 3.
+// This is due to the fact that the const num is defined as 103 and the program will always use that global value as the source of truth.
 
 const num = 103;
 
 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
+// The global value that is defined outside of the function is used as the source of truth.
+// Therefore when the program executes the line return num.toString().slice(-1); it always considers the global value.
+// The console.log ignores the values.
+
 // 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

@@ -14,6 +14,12 @@
 // Then when we call this function with the weight and height
 // It should return their Body Mass Index to 1 decimal place
 
+// solution 1
 function calculateBMI(weight, height) {
-    // return the BMI of someone based off their weight and height
-}
+    const bmi = weight / (height ** 2);
+    return Number(bmi.toFixed(1));
+}
+console.log(`My BMI is: ${calculateBMI(55, 1.3)}`)
+
+// solution 2
+// To make this program fit for real world use, I would implement a conversion for various metrics used for height and weight.

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

@@ -14,3 +14,8 @@
 // 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
+// Solution
+function toUpperSnakeCase(str) {
+    return str.toUpperCase().replaceAll(" ","_");
+}
+console.log(ToUpperSnakeCase("hello there"));

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

@@ -4,3 +4,17 @@
 // 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
+
+//Solution: 
+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}`;
+}
+
+console.log(toPounds("399p"));
+console.log(toPounds("45p"));
+console.log(toPounds("5p"));
+console.log(toPounds("1200p"));

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

@@ -11,24 +11,34 @@ function formatTimeDisplay(seconds) {
   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
 
+console.log(formatTimeDisplay(61));
+
 // You will need to play computer with this example - use the Python Visualiser https://pythontutor.com/visualize.html#mode=edit
 // to help you answer these questions
 
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
+// Pad will be called three times (for 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
+// The value assigned to num for the first time that it is called is 0 (totalHours = 0)
 
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
+// The return value of pad for its first call is "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 value is 1, when formatTimeDisplay(61) runs: 61 seconds = 1 minute and 1 second
+// remainingSeconds = 61 % 60 = 1
+// The last call to pad is pad(remainingSeconds), so num receives 1
 
 // e) What is the return value assigned to num when pad is called for the last time in this program?  Explain your answer
 // =============> write your answer here
+// The return value is "01" - pad converts the number to a string and ensures it has at least 2 digits using padStart(2, "0")
+// Since "1" has only one digit, a leading zero is added so the value is then "01"