London | 26-ITP-May | Dagim Daniel | Sprint 2 | key-errors

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

@@ -1,13 +1,18 @@
 // Predict and explain first...
-//  =============> write your prediction here
+  // it will be reference error because the variable str is being declared twice, once as a parameter and once inside the function body.
 
 // 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)}`;
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
 }
 
 // =============> write your explanation here
+  // the error is occurring because the variable str is being declared twice, once as a parameter and once inside the function body. 
+  //removing the let keyword would fix this error, for the function to work properly.
+
 // =============> write your new code here
+  let firstCapitalised = capitalise("hello");
+console.log(firstCapitalised);

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

@@ -2,9 +2,9 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
-
+   // i predict that the error will be a syntax error because the variable decimalNumber is being declared twice, once as a parameter and once inside the function body  
 // Try playing computer with the example to work out what is going on
-
+/*
 function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
@@ -13,8 +13,16 @@ function convertToPercentage(decimalNumber) {
 }
 
 console.log(decimalNumber);
-
+*/
 // =============> write your explanation here
-
+  // removing the const keyword would fix this error, for the function to work properly.
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+function convertToPercentage(decimalNumber) {  
+  //decimalNumber = 0.5; // removing this makes work for different inputs 
+  const percentage = `${decimalNumber * 100}%`;
+  return percentage;
+}
+let converted = convertToPercentage(2.8);
+console.log(converted);

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

@@ -1,20 +1,29 @@
 
 // Predict and explain first BEFORE you run any code...
+   // num is not defined at all, so when the function is called it will throw a reference error.
+    // and inside the function the parameter is not defined correctly, it should be num instead of 3.
 
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
-
+// reference error because the parameter is not defined correctly, it should be num instead of 3.
+/* below is the original code 
 function square(3) {
     return num * num;
 }
+*/
 
 // =============> write the error message here
-
+    // the error was syntaxError: unexpected number.
 // =============> explain this error message here
-
+    // because the parameter is not defined correctly, it should be num instead of 3. so the function is not defined correctly and it will throw a syntax error.
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
-
+function square(num) {
+    return num * num;
+
+}       
+let result = square(3);
+console.log(result);
 

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

@@ -1,14 +1,21 @@
 // Predict and explain first...
 
 // =============> write your prediction here
-
+    // there is no return statement in the multiply function, so when we try to log the result of the function call, it will return undefined. 
+/* original code 
 function multiply(a, b) {
   console.log(a * b);
 }
 
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
-
+*/
 // =============> write your explanation here
-
+    // console.log will do  the multiplication of a and b and print the result to the console, but it will not return any value.
+    // there is no operation done here. just for testing purpose not actual operation. 
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+
+function multiply(a, b) {
+  console.log(a * b);
+  return a * b; // new code added to return the result of the multiplication.
+}

Sprint-2/2-mandatory-debug/1.js

@@ -1,13 +1,23 @@
 // Predict and explain first...
 //  =============> write your prediction here
-
+    //we have to delete the semicolon used after the return statement in the sum function, because it will terminate the function and return undefined.
+    /* below is the original code
 function sum(a, b) {
   return;
   a + b;
 }
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
-
+*/
 // =============> write your explanation here
+    // same as my prediction.
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function sum(a, b) {
+  return a + b;   // removed the semicolon after the return statement to fix the problem.
+  // and also assigned the value of a + b to the return statement so that it will return the sum of a and b. 
+  // unlike my prediction removing the semicolon only wont do the fix. because in javascript there is a feature called automatic semicolon insertion which will automatically insert a semicolon after the return statement 
+  // when playing computer with this code  it will read return with out ; as same as with it. - same error result
+}
+
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);

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

@@ -2,8 +2,11 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
-
-const num = 103;
+    // the console.log statement will print the last digit of the number 103, which is 3. for all 3 cases.
+    // since the num variable is declared is global scope, it will always return the last digit of 103.
+    // the function loses the feature of reusability because it is not taking any parameter to work with, it is always working with the global variable num.
+/* original code
+    const num = 103;
 
 function getLastDigit() {
   return num.toString().slice(-1);
@@ -12,13 +15,22 @@ function getLastDigit() {
 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 output is the same as my prediction, it will print the last digit of the number 103, which is 3. for all 3 cases.
 // Explain why the output is the way it is
 // =============> write your explanation here
+    // like i explained in my prediction, since the num variable is declared is global scope, it will always return the last digit of 103.
 // 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

@@ -16,4 +16,9 @@
 
 function calculateBMI(weight, height) {
     // return the BMI of someone based off their weight and height
-}
+      const bmi = weight / (height * height);
+
+    return bmi.toFixed(1); // toFixed() method is used to format the BMI value to 1 decimal place
+}   
+let result = calculateBMI(70, 1.73); // Example usage of the function with weight 70kg and height 1.73m
+console.log(`The BMI is ${result}`); // Output the result to the console.

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

@@ -14,3 +14,12 @@
 // 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(inString) {
+    const outPutString = inString.toUpperCase().replaceAll(" ","_");
+  return outPutString;
+}
+let output1 = toUpperSnakeCase("hello there");
+let output2 = toUpperSnakeCase("lord of the rings");
+console.log(`The result for output1 is : ${output1}. 
+The result for output2 is : ${output2}.`)

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

@@ -4,3 +4,26 @@
 // 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
+    /*
+const penceStringWithoutTrailingP = penceString.substring(0,penceString.length - 1);
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"); // pad the string with leading zeros to ensure it has at least 3 characters
+const pounds = paddedPenceNumberString.substring(0,paddedPenceNumberString.length - 2); // get the substring representing the pounds by taking all characters except the last two
+const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0"); // get the substring representing the pence by taking the last two characters and padding it with a "0" if necessary
+console.log(`£${pounds}.${pence}`); //
+
+    */
+
+function toPounds(penceString){
+const penceStringWithoutTrailingP = penceString.substring(0,penceString.length - 1);
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"); // pad the string with leading zeros to ensure it has at least 3 characters
+const pounds = paddedPenceNumberString.substring(0,paddedPenceNumberString.length - 2); // get the substring representing the pounds by taking all characters except the last two
+const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0"); // get the substring representing the pence by taking the last two characters and padding it with a "0" if necessary
+
+    return `£${pounds}.${pence}`
+}
+let output1 = toPounds("500p");
+let output2 = toPounds("399p");
+let output3 = toPounds("2000p");
+console.log(`${output1}
+${output2}
+${output3}`);

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

@@ -14,25 +14,26 @@ 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
-
+    // 3 times
 // 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 is 0
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
-
+    // the return value 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 last call to pad is with remainingSeconds, which is 1. so num =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
+    // pad returns "01" because it pads the single-digit "1" with a leading "0"