diff --git a/source/auxiliary/to_string.cpp b/source/auxiliary/to_string.cpp
new file mode 100644
index 0000000..e67a776
--- /dev/null
+++ b/source/auxiliary/to_string.cpp
@@ -0,0 +1,51 @@
+
+
+#include <iomanip>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "../auxiliary/to_string.h"
+
+std::string ksi::to_string (const double x)
+{
+   std::stringstream ss;
+   ss << std::scientific << x;
+   return ss.str();
+}
+
+std::string ksi::to_string (const int n, const unsigned int width)
+{
+   std::stringstream ss;
+   ss << std::setw(width) << std::setfill('0') << n;
+   return ss.str();
+}
+
+std::string ksi::to_string (const std::vector<double> & numbers, const char sep)
+{
+   std::stringstream ss;
+   auto size = numbers.size();
+   for (std::size_t i = 0; i < size - 1; ++i)
+   {
+      ss << numbers[i] << sep;
+   }
+   if (size > 0)
+      ss << numbers.back();
+   
+   return ss.str();
+}
+
+std::string ksi::to_string (const std::vector<int> & numbers, const unsigned int width, const char sep)
+{
+   std::stringstream ss;
+   auto size = numbers.size();
+   for (std::size_t i = 0; i < size - 1; ++i)
+   {
+      ss << std::setw(width) << std::setfill('0') << numbers[i] << sep;
+   }
+   if (size > 0)
+      ss << std::setw(width) << std::setfill('0') << numbers.back();
+   
+   return ss.str();
+}
diff --git a/source/auxiliary/to_string.h b/source/auxiliary/to_string.h
new file mode 100644
index 0000000..3a893de
--- /dev/null
+++ b/source/auxiliary/to_string.h
@@ -0,0 +1,41 @@
+/** @file */ 
+
+#ifndef TO_STRING_H
+#define TO_STRING_H
+
+#include <string>
+#include <vector>
+
+namespace ksi
+{
+   /* @return The function returns a string representation of a double value in the exponential form.
+    * @author Krzysztof Siminski
+    * @date 2023-10-09 */ 
+   std::string to_string (const double x);
+
+   /* @return The function returns a string representation of an integer value with leading zeroes.
+    * @author Krzysztof Siminski
+    * @param n number to make a string for
+    * @param width width of the window for an integer (filled with zeroes)
+    * @date 2024-03-27 */ 
+   std::string to_string (const int n, const unsigned int width = 0);
+
+   /* @return The function returns a string representation of a vector of ints with leading zeroes.
+    * @author Krzysztof Siminski
+    * @param numbers numbers to make a string for
+    * @param width width of the window for an integer (filled with zeroes)
+    * @param sep separator of numbers
+    * @date 2024-03-29 */ 
+   std::string to_string (const std::vector<int> & numbers, const unsigned int width = 0, const char sep = '-');
+
+   /* @return The function returns a string representation of a vector of ints with leading zeroes.
+    * @author Krzysztof Siminski
+    * @param numbers numbers to make a string for
+    * @param width width of the window for an integer (filled with zeroes)
+    * @param sep separator of numbers
+    * @date 2024-03-29 */ 
+   std::string to_string (const std::vector<double> & numbers, const char sep = '-');
+}
+
+
+#endif