diff --git a/.gitignore b/.gitignore
index bde36e530..ed63450dc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,6 @@
 node_modules
 .DS_Store
 .vscode
-**/.DS_Store
\ No newline at end of file
+*package.json
+*package-lock.json
+**/.DS_Store
diff --git a/Sprint-3/2-practice-tdd/count.js b/Sprint-3/2-practice-tdd/count.js
index 95b6ebb7d..8903068f9 100644
--- a/Sprint-3/2-practice-tdd/count.js
+++ b/Sprint-3/2-practice-tdd/count.js
@@ -1,5 +1,40 @@
+/**
+ * Original file:
+ *
 function countChar(stringOfCharacters, findCharacter) {
   return 5
 }
 
 module.exports = countChar;
+*
+* End of file
+*/
+
+// Implementation:
+
+/**
+ * Counts the number of times a character occurs in a string
+ * @param {string} str - The string to search 
+ * @param {string} char - The single character to search for
+ * @returns {number} - The count of occurrences
+ */
+function countChar(str, char) {
+  // Input validation
+  if (typeof str !== 'string' || typeof char !== 'string' || char.length !== 1) {
+    return 0;
+  }
+
+  let count = 0;
+
+  // Loop through each character in the string
+  for (let i = 0; i < str.length; i++) {
+    if (str[i] === char) {
+      count++;
+    }
+  }
+
+  return count;
+}
+
+module.exports = countChar;
+
diff --git a/Sprint-3/2-practice-tdd/count.test.js b/Sprint-3/2-practice-tdd/count.test.js
index 179ea0ddf..691947ccc 100644
--- a/Sprint-3/2-practice-tdd/count.test.js
+++ b/Sprint-3/2-practice-tdd/count.test.js
@@ -1,3 +1,6 @@
+/**
+ * Origignal file:
+ * 
 // implement a function countChar that counts the number of times a character occurs in a string
 const countChar = require("./count");
 // Given a string `str` and a single character `char` to search for,
@@ -22,3 +25,55 @@ test("should count multiple occurrences of a character", () => {
 // And a character `char` that does not exist within `str`.
 // When the function is called with these inputs,
 // Then it should return 0, indicating that no occurrences of `char` were found.
+*
+* End of file
+*/
+
+// Implementation:
+
+const countChar = require("./count");
+
+describe("countChar function", () => {
+  test("should count multiple occurrences of a character", () => {
+    const str = "aaaaa";
+    const char = "a";
+    const count = countChar(str, char);
+    expect(count).toEqual(5);
+  });
+
+  test("should return 0 when character does not occur in the string", () => {
+    const str = "hello world";
+    const char = "z";
+    const count = countChar(str, char);
+    expect(count).toEqual(0);
+  });
+
+  // Additional test cases to ensure robustness
+  test("should handle empty string", () => {
+    const str = "";
+    const char = "a";
+    const count = countChar(str, char);
+    expect(count).toEqual(0);
+  });
+
+  test("should handle single occurrence", () => {
+    const str = "hello world";
+    const char = "h";
+    const count = countChar(str, char);
+    expect(count).toEqual(1);
+  });
+
+  test("should handle case sensitivity", () => {
+    const str = "Hello World";
+    const char = "h";
+    const count = countChar(str, char);
+    expect(count).toEqual(0); // 'H' is different from 'h'
+  });
+
+  test("should handle invalid inputs gracefully", () => {
+    expect(countChar(123, "a")).toEqual(0); // Non-string first argument
+    expect(countChar("hello", 123)).toEqual(0); // Non-string second argument
+    expect(countChar("hello", "ab")).toEqual(0); // Multiple characters
+  });
+});
+
diff --git a/Sprint-3/2-practice-tdd/get-ordinal-number.js b/Sprint-3/2-practice-tdd/get-ordinal-number.js
index f95d71db1..d04b8fd00 100644
--- a/Sprint-3/2-practice-tdd/get-ordinal-number.js
+++ b/Sprint-3/2-practice-tdd/get-ordinal-number.js
@@ -1,5 +1,39 @@
+/**
+ * Original file
+ *
 function getOrdinalNumber(num) {
   return "1st";
 }
 
 module.exports = getOrdinalNumber;
+*
+* Enf of file
+*/
+
+function getOrdinalNumber(number) {
+  if (typeof number !== 'number' || !Number.isInteger(number) || number < 0) {
+    throw new Error('Input must be a non-negative integer');
+  }
+
+  // Special case for numbers ending in 11, 12, 13
+  const lastTwoDigits = number % 100;
+  if (lastTwoDigits >= 11 && lastTwoDigits <= 13) {
+    return number + "th";
+  }
+
+  // Check the last digit
+  const lastDigit = number % 10;
+  switch (lastDigit) {
+    case 1:
+      return number + "st";
+    case 2:
+      return number + "nd";
+    case 3:
+      return number + "rd";
+    default:
+      return number + "th";
+  }
+}
+
+module.exports = getOrdinalNumber;
+
diff --git a/Sprint-3/2-practice-tdd/get-ordinal-number.test.js b/Sprint-3/2-practice-tdd/get-ordinal-number.test.js
index adfa58560..3e823d14f 100644
--- a/Sprint-3/2-practice-tdd/get-ordinal-number.test.js
+++ b/Sprint-3/2-practice-tdd/get-ordinal-number.test.js
@@ -1,3 +1,6 @@
+/**
+ * Original file
+ *
 const getOrdinalNumber = require("./get-ordinal-number");
 // In this week's prep, we started implementing getOrdinalNumber.
 
@@ -18,3 +21,107 @@ test("should append 'st' for numbers ending with 1, except those ending with 11"
   expect(getOrdinalNumber(21)).toEqual("21st");
   expect(getOrdinalNumber(131)).toEqual("131st");
 });
+*
+* End of file
+*/
+
+// Implementation
+
+const getOrdinalNumber = require("./get-ordinal-number");
+
+describe("getOrdinalNumber", () => {
+  // Case 1: Numbers ending with 1 (but not 11)
+  test("should append 'st' for numbers ending with 1, except those ending with 11", () => {
+    expect(getOrdinalNumber(1)).toEqual("1st");
+    expect(getOrdinalNumber(21)).toEqual("21st");
+    expect(getOrdinalNumber(101)).toEqual("101st");
+    expect(getOrdinalNumber(131)).toEqual("131st");
+    expect(getOrdinalNumber(1001)).toEqual("1001st");
+  });
+
+  // Case 2: Numbers ending with 2 (but not 12)
+  test("should append 'nd' for numbers ending with 2, except those ending with 12", () => {
+    expect(getOrdinalNumber(2)).toEqual("2nd");
+    expect(getOrdinalNumber(22)).toEqual("22nd");
+    expect(getOrdinalNumber(102)).toEqual("102nd");
+    expect(getOrdinalNumber(132)).toEqual("132nd");
+    expect(getOrdinalNumber(1002)).toEqual("1002nd");
+  });
+
+  // Case 3: Numbers ending with 3 (but not 13)
+  test("should append 'rd' for numbers ending with 3, except those ending with 13", () => {
+    expect(getOrdinalNumber(3)).toEqual("3rd");
+    expect(getOrdinalNumber(23)).toEqual("23rd");
+    expect(getOrdinalNumber(103)).toEqual("103rd");
+    expect(getOrdinalNumber(133)).toEqual("133rd");
+    expect(getOrdinalNumber(1003)).toEqual("1003rd");
+  });
+
+  // Case 4: Numbers ending with 11, 12, or 13
+  test("should append 'th' for numbers ending with 11, 12, or 13", () => {
+    expect(getOrdinalNumber(11)).toEqual("11th");
+    expect(getOrdinalNumber(12)).toEqual("12th");
+    expect(getOrdinalNumber(13)).toEqual("13th");
+    expect(getOrdinalNumber(111)).toEqual("111th");
+    expect(getOrdinalNumber(112)).toEqual("112th");
+    expect(getOrdinalNumber(113)).toEqual("113th");
+    expect(getOrdinalNumber(1011)).toEqual("1011th");
+    expect(getOrdinalNumber(1012)).toEqual("1012th");
+    expect(getOrdinalNumber(1013)).toEqual("1013th");
+  });
+
+  // Case 5: All other numbers (should get "th")
+  test("should append 'th' for all other numbers", () => {
+    // Numbers ending with 0
+    expect(getOrdinalNumber(0)).toEqual("0th");
+    expect(getOrdinalNumber(10)).toEqual("10th");
+    expect(getOrdinalNumber(20)).toEqual("20th");
+    expect(getOrdinalNumber(100)).toEqual("100th");
+
+    // Numbers ending with 4-9
+    expect(getOrdinalNumber(4)).toEqual("4th");
+    expect(getOrdinalNumber(5)).toEqual("5th");
+    expect(getOrdinalNumber(6)).toEqual("6th");
+    expect(getOrdinalNumber(7)).toEqual("7th");
+    expect(getOrdinalNumber(8)).toEqual("8th");
+    expect(getOrdinalNumber(9)).toEqual("9th");
+
+    // Larger numbers ending with 4-9
+    expect(getOrdinalNumber(24)).toEqual("24th");
+    expect(getOrdinalNumber(35)).toEqual("35th");
+    expect(getOrdinalNumber(46)).toEqual("46th");
+    expect(getOrdinalNumber(57)).toEqual("57th");
+    expect(getOrdinalNumber(68)).toEqual("68th");
+    expect(getOrdinalNumber(79)).toEqual("79th");
+  });
+
+  // Edge cases
+  describe("edge cases", () => {
+    test("should handle zero", () => {
+      expect(getOrdinalNumber(0)).toEqual("0th");
+    });
+
+    test("should handle large numbers", () => {
+      expect(getOrdinalNumber(1000000)).toEqual("1000000th");
+      expect(getOrdinalNumber(1000001)).toEqual("1000001st");
+      expect(getOrdinalNumber(1000002)).toEqual("1000002nd");
+      expect(getOrdinalNumber(1000003)).toEqual("1000003rd");
+      expect(getOrdinalNumber(1000011)).toEqual("1000011th");
+    });
+
+    test("should throw error for negative numbers", () => {
+      expect(() => getOrdinalNumber(-1)).toThrow("Input must be a non-negative integer");
+    });
+
+    test("should throw error for non-integer numbers", () => {
+      expect(() => getOrdinalNumber(1.5)).toThrow("Input must be a non-negative integer");
+    });
+
+    test("should throw error for non-number inputs", () => {
+      expect(() => getOrdinalNumber("1")).toThrow("Input must be a non-negative integer");
+      expect(() => getOrdinalNumber(null)).toThrow("Input must be a non-negative integer");
+      expect(() => getOrdinalNumber(undefined)).toThrow("Input must be a non-negative integer");
+    });
+  });
+});
+
diff --git a/Sprint-3/2-practice-tdd/repeat-str.js b/Sprint-3/2-practice-tdd/repeat-str.js
index 3838c7b00..e55d6619a 100644
--- a/Sprint-3/2-practice-tdd/repeat-str.js
+++ b/Sprint-3/2-practice-tdd/repeat-str.js
@@ -1,5 +1,44 @@
+/**
+ * Origina file
+ *
 function repeatStr() {
   return "hellohellohello";
 }
 
 module.exports = repeatStr;
+*
+* End of file
+*/
+
+/**
+ * @param {string} str - The string to repeat
+ * @param {number} count - The number of times to repeat the string (must be non-negative)
+ * @returns {string} The repeated string
+ * @throws {Error} When count is negative
+ */
+function repeatStr(str, count) {
+  // Input validation
+  if (typeof str !== 'string') {
+    throw new Error('First argument must be a string');
+  }
+
+  if (typeof count !== 'number' || !Number.isInteger(count)) {
+    throw new Error('Count must be an integer');
+  }
+
+  // Handle negative count
+  if (count < 0) {
+    throw new Error('Count must be a positive integer');
+  }
+
+  // Handle count of 0
+  if (count === 0) {
+    return "";
+  }
+
+  // Use built-in repeat method for efficiency
+  return str.repeat(count);
+}
+
+module.exports = repeatStr;
+
diff --git a/Sprint-3/2-practice-tdd/repeat-str.test.js b/Sprint-3/2-practice-tdd/repeat-str.test.js
index a3fc1196c..26739f112 100644
--- a/Sprint-3/2-practice-tdd/repeat-str.test.js
+++ b/Sprint-3/2-practice-tdd/repeat-str.test.js
@@ -1,3 +1,6 @@
+/**
+ * Original file:
+ *
 // Implement a function repeatStr
 const repeatStr = require("./repeat-str");
 // Given a target string `str` and a positive integer `count`,
@@ -30,3 +33,68 @@ test("should repeat the string count times", () => {
 // Given a target string `str` and a negative integer `count`,
 // When the repeatStr function is called with these inputs,
 // Then it should throw an error, as negative counts are not valid.
+*
+* Enf of file
+*/
+
+// Implementation:
+
+const repeatStr = require("./repeat-str");
+
+describe("repeatStr function", () => {
+  // Test case 1: Multiple repetitions (count > 1)
+  test("should repeat the string count times when count > 1", () => {
+    const str = "hello";
+    const count = 3;
+    const repeatedStr = repeatStr(str, count);
+    expect(repeatedStr).toEqual("hellohellohello");
+  });
+
+  // Test case 2: Count equal to 1
+  test("should return the original string when count is 1", () => {
+    const str = "hello";
+    const count = 1;
+    const repeatedStr = repeatStr(str, count);
+    expect(repeatedStr).toEqual("hello");
+  });
+
+  // Test case 3: Count equal to 0
+  test("should return empty string when count is 0", () => {
+    const str = "hello";
+    const count = 0;
+    const repeatedStr = repeatStr(str, count);
+    expect(repeatedStr).toEqual("");
+  });
+
+  // Test case 4: Negative count
+  test("should throw an error when count is negative", () => {
+    const str = "hello";
+    const count = -1;
+    expect(() => {
+      repeatStr(str, count);
+    }).toThrow("Count must be a positive integer");
+  });
+
+  // Additional test cases for robustness
+  describe("edge cases", () => {
+    test("should handle empty string", () => {
+      expect(repeatStr("", 5)).toEqual("");
+    });
+
+    test("should handle string with spaces", () => {
+      expect(repeatStr("a b ", 2)).toEqual("a b a b ");
+    });
+
+    test("should throw error when count is not an integer", () => {
+      expect(() => {
+        repeatStr("hello", 3.5);
+      }).toThrow("Count must be an integer");
+    });
+
+    test("should throw error when first argument is not a string", () => {
+      expect(() => {
+        repeatStr(123, 3);
+      }).toThrow("First argument must be a string");
+    });
+  });
+});