West Midlands | 25 Sep ITP | Iswat Bello | Sprint 2 | Module Structuring and Testing Data Coursework Sprint 2

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

@@ -1,13 +1,29 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// Answer
+// If I call the function capitalise with a string input, I predict that it will return an error because the variable str
+// has already been declared as a paramter of the function so it can not be re-declared
 
 // 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;
+//}
+
+// =============> write your explanation here
+//Answer
+// The error message "SyntaxError: Identifier 'str' has already been declared" means that the identifier "str" has been declared and so can not be re-declared.
+// This error occured because the same variable name occurs as a function parameter and is then redeclared using a let assignment in a function body again.
+// Redeclaring the same variable within the same function or block scope using let is not allowed in JavaScript.
+
+// =============> write your new code here
+// Answer
 function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+let actualOutput = capitalise("welcome");
+console.log(actualOutput);

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

@@ -2,19 +2,53 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// Prediction
+// An error will occur when the program runs because a variable cannot be redeclared.
+// The parameter "decimalNumber" is already a declared variable, so it cannot be redeclared again using const decimalNumber = 0.5; inside the same function.
+
 
 // Try playing computer with the example to work out what is going on
 
-function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
-  const percentage = `${decimalNumber * 100}%`;
+//function convertToPercentage(decimalNumber) {
+  //const decimalNumber = 0.5;
+  //const percentage = `${decimalNumber * 100}%`;
 
-  return percentage;
-}
+  //return percentage;
+//}
 
-console.log(decimalNumber);
+//console.log(decimalNumber);
 
 // =============> write your explanation here
+// Explanation
+//function convertToPercentage(decimalNumber) {
+  //const decimalNumber = 0.5;
+  //const percentage = `${decimalNumber * 100}%`;
+
+  //return percentage;
+//}
+
+// When the script starts, JavaScript defines the function convertToPercentage, but it doesn’t run it yet.
+// This means that nothing is executed inside the function; only the function itself is stored in memory.
+
+// console.log(decimalNumber);
+// At this point, JavaScript looks for a variable called decimalNumber in the current scope (the global scope), but none exists. 
+// We only declared decimalNumber as a parameter inside the function (which hasn’t been called yet).
+// Result: Because decimalNumber isn’t defined globally, JavaScript will throw an error
+// At this point, JavaScript looks for a variable called decimalNumber in the current scope (the global scope).
+// But none exists — we only declared decimalNumber as a parameter inside the function (which hasn’t been called yet).
+// Error message: "SyntaxError: Identifier 'decimalNumber' has already been declared"
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+decimalNumber = 0.5;
+function convertToPercentage(decimalNumber) {
+
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+const actualOutput = convertToPercentage(15);
+console.log(actualOutput);
+console.log(decimalNumber);

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

@@ -4,17 +4,29 @@
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+// When the code is being read or parsed by Node, it will throw a syntax error because it cannot interpret the number 3 inside the parentheses.
+// This is because a number (3) is not a valid parameter name in a function definition.
 
-function square(3) {
-    return num * num;
-}
 
-// =============> write the error message here
+//function square(3) {
+  //  return num * num;
+//}
 
+// =============> write the error message here
+// SyntaxError: Unexpected number
 // =============> explain this error message here
+// This error message indicates that JavaScript only allows identifiers as parameters in a function definition.  
+// If a literal value (such as a number, string, or object) is used instead, a SyntaxError will be thrown.
+
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
+function square(num) {
+    return num * num;
+}
+
+const actualOutput = square(3);
+console.log(actualOutput);
 
 

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

@@ -1,14 +1,37 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+// Answer
+// If this program runs, I predict that the function will return undefined because it has no return statement. 
+// Also, the console.log inside the multiply function will print its output to the terminal.
+// Lastly, because the function returns undefined, when ${multiply(10, 32)} is used inside a template literal inside the console.log function, it will print undefined in that position.
 
-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
+// Explanation
+// function multiply(a, b) {}
+// This expression defines a function named multiply.
+// The function takes two parameters: a and b.
+
+// console.log(a * b);
+// This expression multipies a and b and prints the result in the terminal.
+// There is no return statement, so the function implicitly returns undefined.
+
+// console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+// In this expression, multiply(10, 32) is called.
+// Because the function returns undefined, the template literal becomes: "The result of multiplying 10 and 32 is undefined"
+// That string is printed to the console.
 
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function multiply(a, b) {
+  console.log(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 +1,46 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// Answer
+// I predict that calling sum(10, 32) will return `undefined`.
+// This is because the `return` statement has a semicolon immediately after it, 
+// so JavaScript interprets it as `return;` which evaluate to "undefined" when the function is called
+// The expression `a + b` on the next line will never be executed.
+// Therefore, any console.log using sum(10, 32) will display `undefined` in the output.
 
-function sum(a, b) {
-  return;
-  a + b;
-}
 
-console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+//function sum(a, b) {
+  //return;
+  //a + b;
+//}
+
+//console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+// Explanation
+// function sum(a, b) {
+// This declares a function named sum that takes two parameters: a and b.
+
+// return;
+// The return statement is immediately followed by a semicolon.
+// This causes the function to exit immediately.
+// Since nothing is returned explicitly, JavaScript returns undefined by default.
+
+//   a + b;
+// This line never executes because the function has already exited at the `return;` line.
+
+// console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+// In this expression, sum(10, 32) is called.
+// Because the function returns undefined, the template literal becomes: "The sum of 10 and 32 is undefined"
+// That string is printed to the console.
+
 // Finally, correct the code to fix the problem
+// I will fix the error by placing the expression a + b on the same line as the return statement.
+// Optionally, I can use parentheses around the expression, but this is not required.
+
 //  =============> 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 +2,43 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+// Prediction
+// When the function is called, I predict that the output will always be 3.
+// This is because the variable 'num' is defined outside the function and is always 103.
+// Therefore, regardless of the argument passed to getLastDigit, it will always return the last digit of 103, which is 3.
 
-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
+// Output
+// 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
+// Explanation
+// The output will always be 3 because the function getLastDigit does not have a parameter so can not accept any arguments.
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+// New code
+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

@@ -16,4 +16,10 @@
 
 function calculateBMI(weight, height) {
     // return the BMI of someone based off their weight and height
-}
+    let bmi = weight / (height * height);
+    bmi = Number(bmi.toFixed(1));
+    return bmi;
+}
+
+let actualOutput = calculateBMI(70, 1.73);
+console.log(actualOutput); // 23.4

prep/sprint-1/example.js

@@ -0,0 +1,13 @@
+// Write a function that will calculate the area of a rectangle
+//given its width and height
+
+let width = 3;
+let height = 4;
+
+function calculateArea(width , height) {
+    const area = width * height;
+    return area;
+}
+
+const result = calculateArea(3,4+8);
+console.log(result);

prep/sprint-1/example2.js

@@ -0,0 +1,11 @@
+function capitaliseFirstLetter(name) {
+  return (name[0].toUpperCase() + name.substring(1));
+}
+
+function createGreeting(name) {
+  const result = capitaliseFirstLetter(name);
+  return `Welcome ${result}`;
+}
+
+const greeting = createGreeting("barath");
+console.log(greeting);

prep/sprint-2/assertions-exercise.js

@@ -0,0 +1,25 @@
+// const calculation = 10 + 32;
+// const result = 40;
+// console.assert(calculation === result);
+
+// function formatAs12HourClock() {}
+// console.log(formatAs12HourClock())
+// console.assert(formatAs12HourClock("08:00") === "08:00 am" , `current output: ${formatAs12HourClock("08:00")} , target output: 08:00 am`);
+
+function formatAs12HourClock(time) {
+  return `${time} am`;
+}
+
+const currentOutput = formatAs12HourClock("08:00");
+const targetOutput = "08:00 am";
+console.assert(
+  currentOutput === targetOutput,
+  `current output: ${currentOutput}, target output: ${targetOutput}`
+);
+
+const currentOutput1 = formatAs12HourClock("23:00");
+const targetOutput1 = "11:00 pm";
+console.assert(
+  currentOutput === targetOutput,
+  `current output: ${currentOutput}, target output: ${targetOutput}`
+);

prep/sprint-2/comparing-values.js

@@ -0,0 +1,5 @@
+function formatAs12HourClock() {
+
+}
+
+console.log(formatAs12HourClock("08:00") === "08:00am")