Added working solution for bexp

array/array.c

@@ -0,0 +1,60 @@
+#include "array.h"
+
+struct var_int_array {
+	int* data;
+	size_t size;
+	size_t capacity;
+};
+
+varray* var_int_array_new() {
+	varray* a = malloc(sizeof(struct var_int_array));
+	if (a) {
+		a->size = 0;
+		a->capacity = 10;
+		a->data = malloc(sizeof(int) * a->capacity);
+
+		if (!a->data) {
+			free(a);
+		}
+	}
+	return a;
+}
+
+void var_int_array_destroy(varray* v) {
+	free(v->data);
+	free(v);
+}
+
+size_t var_int_array_size(const varray* v) {
+	return v->size;
+}
+
+int var_int_array_append(varray* v, int value) {
+	if (v->size == v->capacity) {
+		size_t new_cap = v->capacity * 2;
+		int* new = realloc(v->data, new_cap);
+
+		if (!new) {
+			return 0;
+		}
+
+		v->data = new;
+		v->capacity = new_cap;
+	}
+
+	v->data[v->size++] = value;
+	return 1;
+}
+
+int var_int_array_pop(varray* v) {
+	return v->data[--v->size];
+}
+
+int var_int_array_get(const varray* v, size_t idx) {
+	return v->data[idx];
+}
+
+void var_int_array_put(varray* v, size_t idx, int val) {
+	v->data[idx] = val;
+}
+

array/array.h

@@ -0,0 +1,19 @@
+#ifndef ARRAY_H_INCLUDED
+#define ARRAY_H_INCLUDED
+#include <stdlib.h>
+
+struct var_int_array;
+typedef struct var_int_array varray;
+
+varray* var_int_array_new();
+void var_int_array_destroy(varray*);
+
+size_t var_int_array_size(const varray*);
+
+int var_int_array_append(varray*, int value);
+int var_int_array_pop(varray*);
+
+int var_int_array_get(const varray*, size_t idx);
+void var_int_array_put(varray*, size_t idx, int val);
+
+#endif

bexp/bexp.c

@@ -55,19 +55,19 @@ int bexp_loop(value* result, const expression* ex, compute_func compute) {
 }
 
 int compute_and(char* r, int a, int b, int* _) { *r += a && b; return 0; }
-int compute_or(char* r, int a, int b, int* _) { *r += a && b; return 0; }
-int compute_xor(char* r, int a, int b, int* _) { *r += a && b; return 0; }
+int compute_or(char* r, int a, int b, int* _) { *r += a || b; return 0; }
+int compute_xor(char* r, int a, int b, int* _) { *r += a ^ b; return 0; }
 int compute_gt(char* r, int a, int b, int* _) { *r += a > b; return a != b; }
 int compute_lt(char* r, int a, int b, int* _) { *r += a < b; return a != b; }
 
 int compute_plus(char* r, int a, int b, int* c) {
     *r += a ^ b ^ *c;
-    *c = a && b || ((a ^ b) && *c);
+    *c = (a && b) || ((a ^ b) && *c);
     return 0;
 }
 
-int compute_compl(char* r, int a, int _, int* __) { *r = !a; return 0; }
-int compute_not(char* r, int a, int _, int* __) { *r = !a; return a; }
+int compute_compl(char* r, int a, int _, int* __) { *r += !a; return 0; }
+int compute_not(char* r, int a, int _, int* __) { *r += !a; return a; }
 
 compute_func bexp_compute(const operator_t op) {
     switch (op) {
@@ -95,15 +95,18 @@ int bexp_length(const expression* ex) {
     case PLUS: {
         const int l1 = value_length(&ex->value1);
         const int l2 = value_length(&ex->value2);
+        const int max = l1 > l2 ? l1 : l2;
 
-        // handle overflow
-        if (l1 == l2 && l1 > 0 &&
-            *(ex->value1.end - 1) == '1' &&
-            *(ex->value2.end - 1) == '1') {
-            return l1 + 1;
-        } else {
-            return l1 > l2 ? l1 : l2;
+        char tmp[max + 1];
+        tmp[max] = '0';
+
+        value result = { tmp, tmp + max + 1 };
+
+        if (!bexp_loop(&result, ex, compute_plus)) {
+            return -1;
         }
+
+        return tmp[max] == '1' ? max + 1 : max;
     }
 
     case GREATER_THAN:

bexp/bexp_calculator.c

@@ -9,21 +9,31 @@ typedef struct stack {
     value first;
     struct stack* next;
     char container[];
-} stack_t;
+} expr_stack_t;
 
-stack_t* tos = NULL;
+static void read_word();
+static void read_value();
+static void read_command();
+static void discard();
+static int ensure(char* str);
+static void print_value(const value* val);
+static void read_command();
 
-void read_value();
-void read_command();
-void discard();
+static expr_stack_t* tos = NULL;
+
+int main() {
+    while(!feof(stdin)) {
+        read_word();
+    }
+}
 
 void discard() {
-    fprintf(stderr, "Value is malformed. Discarding until space...\n");
-    while(isspace(getchar()));
+    fprintf(stderr, "Input malformed. Discarding until space...\n");
+    while(!isspace(getchar()));
     return;
 }
 
-int read_word() {
+void read_word() {
     char c;
     while (isspace(c = getchar()));
     ungetc(c, stdin);
@@ -36,7 +46,7 @@ int read_word() {
 
 void read_value() {
     int str_size = 10;
-    stack_t* new = malloc(sizeof(stack_t) + str_size * sizeof(char));
+    expr_stack_t* new = malloc(sizeof(expr_stack_t) + str_size * sizeof(char));
     if (!new) {
         perror("Cannot allocate new stack element");
         return;
@@ -44,9 +54,9 @@ void read_value() {
     new->next = tos;
 
     int count = 0;
-    char c;
+    int c;
     while(!isspace(c = getchar())) {
-        if (c != '0' || c != '1') {
+        if (c != '0' && c != '1') {
             free(new);
             discard();
             return;
@@ -56,7 +66,7 @@ void read_value() {
 
         if (str_size == count) {
             str_size *= 2;
-            new = realloc(new, sizeof(stack_t) + str_size * sizeof(char));
+            new = realloc(new, sizeof(expr_stack_t) + str_size * sizeof(char));
             if (!new) {
                 perror("Cannot allocate new stack element");
                 free(new);
@@ -65,13 +75,25 @@ void read_value() {
         }
     }
 
+    // reverse the string in container to match least to most significant order
+    // in bexp
+    char* i = new->container;
+    char* j = new->container + count - 1;
+    while (i < j) {
+        char tmp = *i;
+        *i = *j;
+        *j = tmp;
+        i++;
+        j--;
+    }
+
     new->first.begin = new->container;
     new->first.end = new->container + count;
     tos = new;
 }
 
 int ensure(char* str) {
-    while (str) {
+    while (*str) {
         if (tolower(getchar()) != *str) {
             return 0;
         }
@@ -81,8 +103,8 @@ int ensure(char* str) {
 }
 
 void print_value(const value* val) {
-    char* v = val->begin;
-    while (v != val->end) putchar(*(v++));
+    char* v = val->end - 1;
+    while (v >= val->begin) putchar(*(v--));
     putchar('\n');
 }
 
@@ -118,7 +140,7 @@ void read_command() {
                           printf("empty\n");
                       } else {
                           print_value(&(tos->first));
-                          stack_t* t = tos;
+                          expr_stack_t* t = tos;
                           tos = tos->next;
                           free(t);
                       }
@@ -134,18 +156,29 @@ void read_command() {
         return;
     }
 
-    expression_t ex = { op, tos->value, binary ? tos->next->value : NULL };
+    const static value dummy = { NULL, NULL };
+    expression ex = { op, tos->first, binary ? tos->next->first : dummy };
     int length = bexp_length(&ex);
 
-    char* result = malloc(sizeof(stack_t) + sizeof(char) * length);
-    if (!result) {
+    expr_stack_t* new_tos = malloc(sizeof(expr_stack_t) + sizeof(char) * length);
+    if (!new_tos) {
         perror("Cannot allocate space for result");
         return;
     }
-    value v_result = { result, result + length };
-
-    bexp_evaluate(&v_result, &ex);
-    stack_t
+    new_tos->first.begin = new_tos->container;
+    new_tos->first.end = new_tos->container + length;
 
+    bexp_evaluate(&new_tos->first, &ex);
+    expr_stack_t* new_next = tos->next;
+    free(tos);
+    tos = new_next;
 
+    if (binary) {
+        new_next = tos->next;
+        free(tos);
+        tos = new_next;
+    }
+
+    new_tos->next = tos;
+    tos = new_tos;
 }

func_pointers/collection.c

@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+struct collection {
+	int* values;
+	size_t size;
+	size_t capacity;
+};
+
+void collection_print(struct collection * c, void(*f)(int)) {
+	for (size_t i = 0; i < c->size; i++) {
+		(*f)(c->values[i]);
+	}
+}
+
+struct collection * new_random_collection() {
+	struct collection* new = malloc(sizeof(struct collection));
+	if (!new) {
+		return NULL;
+	}
+
+	new->size = 50;
+	new->capacity = 100;
+	new->values = malloc(new->capacity * sizeof(int));
+	if (!new->values) {
+		free(new);
+		return NULL;
+	}
+
+	for (size_t i = 0; i < new->size; i++) {
+		new->values[i] = rand();
+	}
+
+	return new;
+}
+
+void collection_delete(struct collection *c) {
+	free(c->values);
+	free(c);
+}
+
+void pretty_print(int b) {
+	printf("%d, ", b);
+}
+
+int main() {
+	struct collection* c;
+	c = new_random_collection();
+	collection_print(c, pretty_print);
+	collection_delete(c);
+}