Completed 1-key exercies and 2-mandatory-errors

Author: MehrozMunir

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

@@ -1,2 +1,4 @@
-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?
+//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?
+
+//we can solve this by making the above statements as comments using //

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

@@ -1,4 +1,12 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+//const age = 33;
+//age = age + 1;
+
+/* the mistake in the above code is the use of const which we use only to save the constant values
+which we don't want to change in the future; therefore, in the above example we would declare age
+as a variable rather than constant to solve the issue.*/
+
+let age = 33;
 age = age + 1;
+console.log(age);

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

@@ -3,3 +3,5 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+//the above code is not working because you are printing or using the cityOfBirth constant before initializing it

Sprint-1/2-mandatory-errors/3.js

@@ -1,9 +1,18 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+//const last4Digits = cardNumber.slice(-4);
 
 // 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
+
+//I predicted that the code is not working because the cardNumber is a constant value and cannot be changed
+// but actually we are not changing the value of cardNumber we are just slicing it which will be stored in a different variable
+//and the cardNumber value will remain the same
+//After running the code, I have realized that the code is not working because cardNumber is a number and the slice is a method in String class
+//so, in order to make it work, we need to change cardNumber to String before calling the slice method
+
+const last4Digits = (cardNumber + "").slice(-4);
+console.log("Last four digits of card are : " + last4Digits);

Sprint-1/2-mandatory-errors/4.js

@@ -1,2 +1,9 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+//const 12HourClockTime = "20:53";
+//const 24hourClockTime = "08:53";
+
+const twelveHourClockTime = "20:53";
+const twentyFourhourClockTime = "08:53";
+
+/*in javascript and also many other programming languages, we can't start the name of an identifier
+//  with a number, therefore, I have changed that to text form*/
+