Add data conversion functions

C++/include/utils/data_validation.hpp

@@ -0,0 +1,64 @@
+/*
+    Data validation
+    ---------------
+    This utility function contains two sub-funtions :
+
+    1) make_upper_case() : converts the characters in a string to upper case .
+
+    2) make_lower_case() : converts the characters in a string to lower case . 
+
+    Time complexity
+    ---------------
+    O(n), where n is the length of the string .
+*/
+
+#ifndef DATA_VALIDATION_HPP
+#define DATA_VALIDATION_HPP
+
+#include <string>
+
+using std::string;
+
+/*
+    make_upper_case()
+    -----------------
+    This function returns a given string into upper case . 
+    Loop invariant : Selects each character and converts it to upper case .
+
+    Return value
+    ------------
+    string having all the characters in upper case .
+*/
+
+string make_upper_case(string str)
+{
+    //converting each character to upper case using for loop
+    for (auto &c : str)
+    {
+        c = std::toupper(c); // using the function toupper() for conversion
+    }
+    return str; // returning the converted string
+}
+
+/*
+    make_lower_case()
+    -----------------
+    This function returns a give string into lower case .
+    Loop invariant : Selects each character and converts it to lower case .
+
+    Return value
+    ------------
+    string having all the characters in lower case .
+*/
+
+string make_lower_case(string str)
+{
+    // converting each character to lower case using for loop
+    for (auto &c : str)
+    {
+        c = std::tolower(c); //using the function tolower() for conversion
+    }
+    return str; //returning the converted string
+}
+
+#endif // DATA_VALIDATION_HPP

C++/test/utils/data_validation.cpp

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+#include "third_party/catch.hpp"
+#include "utils/data_validation.hpp"
+
+TEST_CASE("Base cases", "[string][data_validation]")
+{
+    REQUIRE(make_upper_case("cats") == "CATS");
+    REQUIRE(make_upper_case("dogs") == "DOGS");
+    REQUIRE(make_lower_case("CATS") == "cats");
+    REQUIRE(make_lower_case("dogs") == "DOGS");
+}
+
+TEST_CASE("Mixed cases", "[string][data-validation]")
+{
+    REQUIRE(make_upper_case("cAts") == "CATS");
+    REQUIRE(make_upper_case("dOgs") == "DOGS");
+    REQUIRE(make_upper_case("dOGS") == "DOGS");
+    REQUIRE(make_lower_case("CaTS") == "cats");
+    REQUIRE(make_lower_case("DoGS") == "dogs");
+    REQUIRE(make_lower_case("dogS") == "DOGS");
+}