Predicted, explained and fixed code errors

Author: leigh-ross

Sprint-3/2-mandatory-debug/2.js

@@ -2,23 +2,44 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+// Nothing is going to run properly because the function does not have any parameters.
+// I think everything will get a syntax error
 
-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
+// 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
+// I was wrong in my prediction. Code runs.
+// It says the last digit is 3 for every number which is wrong
+// This is because we declared the var num = 103 globally, and it is affecting all the fucntion calls
+// Because of the global declaration, every function call is going to use the global num 
+// This is bad because the code is now taking in diferent parameters but returning a value based on one global value.
+// TO fix this we remove the global var num.
+// Then we add num as a parameter in the function :getLastDigit(num)
+
 // 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