diff --git a/Sprint-2/debug/address.js b/Sprint-2/debug/address.js
index 940a6af83..36d2f865d 100644
--- a/Sprint-2/debug/address.js
+++ b/Sprint-2/debug/address.js
@@ -12,4 +12,4 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address.houseNumber}`);
diff --git a/Sprint-2/debug/author.js b/Sprint-2/debug/author.js
index 8c2125977..f035f3104 100644
--- a/Sprint-2/debug/author.js
+++ b/Sprint-2/debug/author.js
@@ -10,7 +10,7 @@ const author = {
   age: 40,
   alive: true,
 };
-
-for (const value of author) {
-  console.log(value);
+//console.log(author);
+for (const key in author) {
+  console.log(author[key]);
 }
diff --git a/Sprint-2/debug/recipe.js b/Sprint-2/debug/recipe.js
index 6cbdd22cd..dc17ba737 100644
--- a/Sprint-2/debug/recipe.js
+++ b/Sprint-2/debug/recipe.js
@@ -10,6 +10,8 @@ const recipe = {
   ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
 };
 
-console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+console.log(`${recipe.title} serves ${recipe.serves}`);
+console.log("ingredients:");
+for(const item of recipe.ingredients){
+  console.log(item);
+}
\ No newline at end of file
diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index cd779308a..34ff1dc11 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,3 +1,12 @@
-function contains() {}
+function contains(inputObject,inputProperty) {
+    if (
+      inputObject === null ||
+      typeof inputObject !== "object" ||
+      Array.isArray(inputObject)
+    ) {
+      return false;
+    }
+    return inputObject.hasOwnProperty(inputProperty);
+}
 
 module.exports = contains;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 326bdb1f2..6b5b65f95 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -20,16 +20,43 @@ as the object doesn't contains a key of 'c'
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
 
+test("contains on empty object returns false",()=>{
+    const obj = {};
+    const result = contains(obj, "a");
+    expect(result).toBe(false);
+  });
+      
+  
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("object contains an existing property name", () => {
+  const obj = { a: 1, b: 2 };
+  const result = contains(obj, "a");
+  expect(result).toBe(true);
+});
+
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("object contains with a non-existent property name", () => {
+  const obj = { a: 1, b: 2 };
+  const result = contains(obj, "c");
+  expect(result).toBe(false);
+});
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("Given invalid parameters like an array",() => {
+    const obj = ["a",1,"b", 2 ];
+    const result = contains(obj, "a");
+    expect(result).toBe(false);
+});
+test("Given invalid parameters like an array2", () => {
+  const obj = ["a", 1, "b", 2];
+  const result = contains(obj, "1");
+  expect(result).toBe(false);
+});
\ No newline at end of file
diff --git a/Sprint-2/implement/lookup.js b/Sprint-2/implement/lookup.js
index a6746e07f..4d98cfc8c 100644
--- a/Sprint-2/implement/lookup.js
+++ b/Sprint-2/implement/lookup.js
@@ -1,5 +1,14 @@
-function createLookup() {
-  // implementation here
+
+function createLookup(countryCurrArray) {
+    if (
+      !Array.isArray(countryCurrArray) ||
+      !countryCurrArray.every((item) => Array.isArray(item))
+    ) {
+      return null;
+    } 
+    return Object.fromEntries(countryCurrArray);
+  
+ 
 }
 
-module.exports = createLookup;
+module.exports = createLookup;
\ No newline at end of file
diff --git a/Sprint-2/implement/lookup.test.js b/Sprint-2/implement/lookup.test.js
index 547e06c5a..9df2f87dc 100644
--- a/Sprint-2/implement/lookup.test.js
+++ b/Sprint-2/implement/lookup.test.js
@@ -1,6 +1,49 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
+test("creates a country currency code lookup for multiple codes",()=>{
+  const array = [
+    ["US", "USD"],
+    ["CA", "CAD"],
+    ["GB", "GBP"],
+  ];
+  const result = createLookup(array);
+  expect(result).toEqual({
+    US: "USD",
+    CA: "CAD",
+    GB: "GBP",
+  });
+}
+);
+
+test("input array is empty", () => {
+  const array = [];
+  const result = createLookup(array);
+  expect(result).toEqual({});
+});
+ 
+test("The input is an array but doesn't contain array elements", () => {
+  const array = [1,2,3,4];
+  const result = createLookup(array);
+  expect(result).toEqual(null);
+});
+
+test("ُThe input is not an array", () => {
+  const array ="US-USD" ;
+  const result = createLookup(array);
+  expect(result).toEqual(null);
+});
+
+test("ُThe input is  an array of strings", () => {
+  const array = ["US:USD","CA:CAD"];
+  const result = createLookup(array);
+  expect(result).toEqual(null);
+});
+
+test("creates a country currency code lookup for one array", () => {
+  const array = [["US", "USD"]];
+  const result = createLookup(array);
+  expect(result).toEqual({US: "USD"});
+});
 
 /*
 
diff --git a/Sprint-2/implement/querystring.js b/Sprint-2/implement/querystring.js
index 45ec4e5f3..f00834174 100644
--- a/Sprint-2/implement/querystring.js
+++ b/Sprint-2/implement/querystring.js
@@ -6,8 +6,9 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    const [key, ...value] = pair.split("=");
+    const strvalue = value.join("=");
+    queryParams[key] = strvalue;
   }
 
   return queryParams;
diff --git a/Sprint-2/implement/querystring.test.js b/Sprint-2/implement/querystring.test.js
index 3e218b789..4b1e1dde3 100644
--- a/Sprint-2/implement/querystring.test.js
+++ b/Sprint-2/implement/querystring.test.js
@@ -10,3 +10,28 @@ test("parses querystring values containing =", () => {
     "equation": "x=y+1",
   });
 });
+
+test("parses querystring values contains one pair", () => {
+  expect(parseQueryString("brand=Tesla")).toEqual({
+    brand: "Tesla",
+  });
+});
+
+test("parses querystring contains more than one pair ",() =>{
+  expect(parseQueryString("sort=lowest&colour=yellow")).toEqual({
+    "sort":"lowest",
+    "colour":"yellow"});
+  });
+
+  test("parses empty querystring", () => {
+    expect(parseQueryString("")).toEqual({});
+  });
+
+  test("parses key without value", () => {
+    expect(parseQueryString("name")).toEqual({name:""});
+  });
+
+ 
+  test("parses key with empty value", () => {
+    expect(parseQueryString("name=")).toEqual({ name: "" });
+  });
diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index f47321812..44ee5e3e4 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -1,3 +1,23 @@
-function tally() {}
+function tally(itemArray) {
+    if (!Array.isArray(itemArray)) {
+        throw new Error("invalid input");
+    }
+   
+    if (itemArray.length == 0 ) {
+      return {};
+    }
+   
+    let countArray={};
+      for(const item of itemArray ){
+         if(countArray.hasOwnProperty(item)){
+                countArray[item]++;
+            }else{
+                countArray[item]=1;
+          }
+        }
+        return countArray;
+        }
+
 
 module.exports = tally;
+ 
\ No newline at end of file
diff --git a/Sprint-2/implement/tally.test.js b/Sprint-2/implement/tally.test.js
index 2ceffa8dd..08765e4d9 100644
--- a/Sprint-2/implement/tally.test.js
+++ b/Sprint-2/implement/tally.test.js
@@ -23,12 +23,34 @@ const tally = require("./tally.js");
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
+test("tally on an empty array returns an empty object",()=>{
+    expect(tally([])).toEqual({});});
+
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test(
+  "tally on an array with duplicate items returns counts for each unique item",()=>{
+    expect(tally(["a", "a", "a","b"])).toEqual({a:3,b:1});
+    
+  }
+);
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("tally on an invalid input like a string should throw an error",()=>{
+    expect(()=>tally("String Test")).toThrow("invalid input")
+});
+
+test("tally on an invalid input like null  should throw an error",()=>{
+  expect(()=>tally()).toThrow("invalid input")
+});
+
+
+test("tally on an array with various input", () => {
+  expect(tally(["a"])).toEqual({ a: 1 });
+  expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+});
+  
\ No newline at end of file
diff --git a/Sprint-2/interpret/invert.js b/Sprint-2/interpret/invert.js
index bb353fb1f..fd9f3d578 100644
--- a/Sprint-2/interpret/invert.js
+++ b/Sprint-2/interpret/invert.js
@@ -10,20 +10,29 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
 }
+module.exports = invert;
 
 // a) What is the current return value when invert is called with { a : 1 }
 
+//{key : 1} because invertedObj.key= value add  a property with the exact name "key" and value "1" to invertedObj.
+
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
 
-// c) What is the target return value when invert is called with {a : 1, b: 2}
+//{key : 2} because first the function add {key:1} to invertedObj and then modify the property and assign value 2 to key "key".
 
+// c) What is the target return value when invert is called with {a : 1, b: 2}
+//{1 : a ,2 : b}
 // c) What does Object.entries return? Why is it needed in this program?
 
+//It returns pairs of keys and values as an Array of pairs.
+
 // d) Explain why the current return value is different from the target output
 
+//Because invertedObj.key means object "invertedObj" has a key property with the exact name "key" and we need to add a key that its name is the value of key property.
+
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
diff --git a/Sprint-2/interpret/invert.test.js b/Sprint-2/interpret/invert.test.js
new file mode 100644
index 000000000..780716239
--- /dev/null
+++ b/Sprint-2/interpret/invert.test.js
@@ -0,0 +1,9 @@
+const invert = require("./invert.js");
+
+test("invert an object with one pair",()=>{
+    expect(invert({a:1})).toEqual({1:"a"});
+});
+
+test("invert an object with more than ne pair", () => {
+  expect(invert({ a: 1 , b : 2})).toEqual({ 1: "a" , 2: "b"});
+});
diff --git a/Sprint-2/package-lock.json b/Sprint-2/package-lock.json
index 9b4c725d6..f19776e49 100644
--- a/Sprint-2/package-lock.json
+++ b/Sprint-2/package-lock.json
@@ -9,7 +9,8 @@
       "version": "1.0.0",
       "license": "ISC",
       "devDependencies": {
-        "jest": "^29.7.0"
+        "jest": "^29.7.0",
+        "prettier": "^3.6.2"
       }
     },
     "node_modules/@ampproject/remapping": {
@@ -3195,6 +3196,21 @@
         "node": ">=8"
       }
     },
+    "node_modules/prettier": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.6.2.tgz",
+      "integrity": "sha512-I7AIg5boAr5R0FFtJ6rCfD+LFsWHp81dolrFD8S79U9tb8Az2nGrJncnMSnys+bpQJfRUzqs9hnA81OAA3hCuQ==",
+      "dev": true,
+      "bin": {
+        "prettier": "bin/prettier.cjs"
+      },
+      "engines": {
+        "node": ">=14"
+      },
+      "funding": {
+        "url": "https://github.com/prettier/prettier?sponsor=1"
+      }
+    },
     "node_modules/pretty-format": {
       "version": "29.7.0",
       "resolved": "https://registry.npmjs.org/pretty-format/-/pretty-format-29.7.0.tgz",
diff --git a/Sprint-2/package.json b/Sprint-2/package.json
index 80c16780f..a9c1082ae 100644
--- a/Sprint-2/package.json
+++ b/Sprint-2/package.json
@@ -10,6 +10,7 @@
   "author": "",
   "license": "ISC",
   "devDependencies": {
-    "jest": "^29.7.0"
+    "jest": "^29.7.0",
+    "prettier": "^3.6.2"
   }
 }