diff --git a/.gitignore b/.gitignore
index b48d248..b1e499b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -55,4 +55,7 @@ Module.symvers
 Mkfile.old
 dkms.conf
 
+# CMake
+build
+
 # End of https://www.toptal.com/developers/gitignore/api/c
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..6ea464c
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,8 @@
+cmake_minimum_required(VERSION 3.25)
+project(sorting_station C)
+
+add_library(stack src/stack_and_queue/stack/stack.c)
+
+add_executable(sorting_station src/stack_and_queue/stack/sorting_station.c)
+target_link_libraries(sorting_station PRIVATE stack)
+target_compile_options(sorting_station PRIVATE -Wall -Wextra -pedantic)
diff --git a/README.md b/README.md
index 8d586e5..ab05d77 100644
--- a/README.md
+++ b/README.md
@@ -9,3 +9,9 @@
 Основная почта: nicholas.shestakov@gmail.com
 
 Телеграм: @Kolya_shesterka
+
+## Инструкции по сборке:
+```console
+$ cmake . -B build
+$ cmake --build build
+```
diff --git a/src/stack_and_queue/stack/sorting_station.c b/src/stack_and_queue/stack/sorting_station.c
new file mode 100644
index 0000000..594698b
--- /dev/null
+++ b/src/stack_and_queue/stack/sorting_station.c
@@ -0,0 +1,156 @@
+#include "stack.h"
+#include <assert.h>
+#include <ctype.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool isOperatorFirstPriority(char c)
+{
+    return c == '*' || c == '/';
+}
+
+bool isOperatorSecondPriority(char c)
+{
+    return c == '+' || c == '-';
+}
+
+// Takes infix form of expression as string and returns pointer to postfix form string. Please, dont forget free memory.
+// Can track unbalanced brackets and correctness of order of numbers and operators. Cant track extraneous symbols.
+// If the error is tracked, returns pointer to the string with the error description.
+char* sortingStation(char* infixForm)
+{
+    char* output = calloc(2 * strlen(infixForm), sizeof(output));
+    Stack* operators = newStack();
+
+    bool isNumberTurn = true; // For check correctness of order.
+    char* errorMessage = calloc(64, sizeof(*errorMessage)); // For error returns.
+    int indexOfOutput = 0;
+    for (int indexOfInfix = 0; infixForm[indexOfInfix] != '\0'; ++indexOfInfix) {
+        if (isdigit(infixForm[indexOfInfix])) {
+            if (!isNumberTurn) {
+                strcat(errorMessage, "Error! Order of numbers and operators is incorrect.");
+            }
+            isNumberTurn = !isNumberTurn;
+
+            output[indexOfOutput] = infixForm[indexOfInfix];
+            output[indexOfOutput + 1] = ' ';
+            indexOfOutput += 2;
+        }
+        if (isOperatorFirstPriority(infixForm[indexOfInfix])) {
+            if (isNumberTurn) {
+                strcat(errorMessage, "Error! Order of numbers and operators is incorrect.");
+            }
+            isNumberTurn = !isNumberTurn;
+
+            push(operators, infixForm[indexOfInfix]);
+        }
+        if (isOperatorSecondPriority(infixForm[indexOfInfix])) {
+            if (isNumberTurn) {
+                strcat(errorMessage, "Error! Order of numbers and operators is incorrect.");
+            }
+            isNumberTurn = !isNumberTurn;
+
+            while (!isEmpty(operators) && peek(operators) != '(') {
+                output[indexOfOutput++] = pop(operators);
+                output[indexOfOutput++] = ' ';
+            }
+            push(operators, infixForm[indexOfInfix]);
+        }
+        if (infixForm[indexOfInfix] == '(') {
+            if (!isNumberTurn) {
+                strcat(errorMessage, "Error! Number before opening bracket.");
+            }
+
+            push(operators, infixForm[indexOfInfix]);
+        }
+        // Многоступенчатость в целях предотвращения одновременного добавления сразу нескольких сообщений об ошибке.
+        if (infixForm[indexOfInfix] == ')') {
+            if (isEmpty(operators)) {
+                strcat(errorMessage, "Error! Brackets not opened.");
+            } else {
+                if (isNumberTurn) {
+                    strcat(errorMessage, "Error! Operator before closing bracket.");
+                } else {
+                    while (peek(operators) != '(') {
+                        output[indexOfOutput++] = pop(operators);
+                        output[indexOfOutput++] = ' ';
+
+                        if (isEmpty(operators)) {
+                            strcat(errorMessage, "Error! Brackets not opened.");
+                            break;
+                        }
+                    }
+                    if (!isEmpty(operators)) {
+                        pop(operators);
+                    }
+                }
+            }
+        }
+
+        // Данное условие истинно, когда строки не равны.
+        if (strcmp(errorMessage, "")) {
+            free(output);
+            deleteStack(operators);
+            return errorMessage;
+        }
+    }
+
+    while (!isEmpty(operators)) {
+        output[indexOfOutput++] = pop(operators);
+        output[indexOfOutput++] = ' ';
+
+        if (output[indexOfOutput - 2] == '(') {
+            free(output);
+            deleteStack(operators);
+            strcat(errorMessage, "Error! Brackets not closed.");
+            return errorMessage;
+        }
+    }
+
+    deleteStack(operators);
+    return output;
+}
+
+int main()
+{
+    char* testSimple = sortingStation("(1 + (4 + 5 / 2) - 3) + (6 + 8)");
+    char* testNoSpaces = sortingStation("4/2+6");
+    char* testManyBrackets = sortingStation("((((1))))");
+    char* testOnlyNumber = sortingStation("1");
+    char* testEmpty = sortingStation("");
+    char* testIncorrectOrder = sortingStation("1 + + 1");
+    char* testIncorrectOrder2 = sortingStation("+ 1");
+    char* testNumberBeforeBracket = sortingStation("1 (+ 3)");
+    char* testOperatorBeforeBracket = sortingStation("1 + (2 + ) 3");
+    char* testBracketsNotOpened = sortingStation("1 + 2)");
+    char* testBracketsNotClosed = sortingStation("1 + (2 + 3");
+
+    assert(!strcmp(testSimple, "1 4 5 2 / + + 3 - 6 8 + + ") && "testSimple incorrect.");
+    assert(!strcmp(testNoSpaces, "4 2 / 6 + ") && "testNoSpaces incorrect.");
+    assert(!strcmp(testManyBrackets, "1 ") && "testManyBrackets incorrect.");
+    assert(!strcmp(testOnlyNumber, "1 ") && "testOnlyNumber incorrect.");
+    assert(!strcmp(testEmpty, "") && "testEmpty incorrect.");
+    assert(!strcmp(testIncorrectOrder, "Error! Order of numbers and operators is incorrect.") && "testIncorrectOrder incorrect.");
+    assert(!strcmp(testIncorrectOrder2, "Error! Order of numbers and operators is incorrect.") && "testIncorrectOrder2 incorrect.");
+    assert(!strcmp(testNumberBeforeBracket, "Error! Number before opening bracket.") && "testNumberBeforeBracket incorrect.");
+    assert(!strcmp(testOperatorBeforeBracket, "Error! Operator before closing bracket.") && "testOperatorBeforeBracket incorrect.");
+    assert(!strcmp(testBracketsNotOpened, "Error! Brackets not opened.") && "testBracketsNotOpened incorrect.");
+    assert(!strcmp(testBracketsNotClosed, "Error! Brackets not closed.") && "testBracketsNotClosed incorrect.");
+
+    printf("All tests passed successfully.\n");
+
+    free(testSimple);
+    free(testNoSpaces);
+    free(testManyBrackets);
+    free(testOnlyNumber);
+    free(testEmpty);
+    free(testIncorrectOrder);
+    free(testIncorrectOrder2);
+    free(testNumberBeforeBracket);
+    free(testOperatorBeforeBracket);
+    free(testBracketsNotOpened);
+    free(testBracketsNotClosed);
+    return 0;
+}
diff --git a/src/stack_and_queue/stack/stack.c b/src/stack_and_queue/stack/stack.c
new file mode 100644
index 0000000..2878e96
--- /dev/null
+++ b/src/stack_and_queue/stack/stack.c
@@ -0,0 +1,60 @@
+#include "stack.h"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct StackNode {
+    int value;
+    struct StackNode* next;
+} StackNode;
+
+struct Stack {
+    StackNode* head;
+};
+
+Stack* newStack()
+{
+    Stack* stack = calloc(1, sizeof(*stack));
+    assert(stack != NULL && "Error! Memory allocated incorrect.");
+    return stack;
+}
+
+void deleteStack(Stack* stack)
+{
+    while (!isEmpty(stack)) {
+        pop(stack);
+    }
+    free(stack);
+}
+
+void push(Stack* stack, int value)
+{
+    StackNode* newNode = malloc(sizeof(*newNode));
+    assert(newNode != NULL && "Error! Memory allocated incorrect.");
+    newNode->value = value;
+    newNode->next = stack->head;
+    stack->head = newNode;
+}
+
+int pop(Stack* stack)
+{
+    assert(!isEmpty(stack) && "Error! Stack is empty. Can`t pop value.");
+    StackNode* poppedNode = stack->head;
+    int value = poppedNode->value;
+    stack->head = poppedNode->next;
+    free(poppedNode);
+    return value;
+}
+
+int peek(Stack* stack)
+{
+    assert(!isEmpty(stack) && "Error! Stack is empty. Can`t peek value.");
+    return stack->head->value;
+}
+
+bool isEmpty(Stack* stack)
+{
+    return stack->head == NULL;
+}
diff --git a/src/stack_and_queue/stack/stack.h b/src/stack_and_queue/stack/stack.h
new file mode 100644
index 0000000..984d7e7
--- /dev/null
+++ b/src/stack_and_queue/stack/stack.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <stdbool.h>
+
+typedef struct Stack Stack;
+
+// Creates new stack.
+// Returns pointer to the created stack.
+Stack* newStack();
+
+// Deletes stack. Frees all memory used in it.
+// Takes pointer to the stack.
+void deleteStack(Stack* stack);
+
+// Pushes new value on the top of the stack.
+// Takes pointer to the stack and value for push.
+void push(Stack* stack, int value);
+
+// Deletes the top value of the stack and returns it. Frees memory used for top node.
+// Takes pointer to the stack.
+// Don`t use if the stack is empty. It causes the error.
+// Check this with isEmpty before use this function.
+int pop(Stack* stack);
+
+// Returns the top value of the stack.
+// Takes pointer to the stack.
+// Don`t use if the stack is empty. It causes the error.
+// Check this with isEmpty before use this function.
+int peek(Stack* stack);
+
+// Returns true if the stack is empty and false if not.
+// Takes pointer to the stack.
+bool isEmpty(Stack* stack);