add cv4

cv4/Makefile

@@ -0,0 +1,13 @@
+CFLAGS= -std=c99 -g -Wall
+
+all: train
+
+%.o: %.c
+	gcc -c -o $@ $< $(CFLAGS)
+
+train: main.o a_train.o
+	gcc main.o a_train.o -o train 
+
+clean:
+	rm *.o train
+

cv4/a_train.c

@@ -0,0 +1,91 @@
+#include "a_train.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct car* add_car(struct car* first,const char* target)
+{
+    struct car* newcar = calloc(1,sizeof(struct car));
+    strcpy(newcar->value, target);
+
+    if(first == NULL)
+    {
+        return newcar;
+    }
+
+    struct car* this = first;
+    
+    while(this->next != NULL)
+    {
+        this = this->next;
+    }
+
+    this->next = newcar;
+
+    return first;
+}
+
+void print_train(struct car* first)
+{
+    if(first == NULL)
+    {
+        return;
+    }
+    struct car* this = first;
+    
+    while(this->next != NULL)
+    {
+        printf("%s\n", this->value);
+        this = this->next;
+    }
+    printf("%s\n", this->value);
+}
+
+void cancel_train(struct car* first)
+{
+    if(first == NULL)
+    {
+        return;
+    }
+    struct car* this = first;
+    if(this->next != NULL)
+    {
+        cancel_train(this->next);
+    }
+    free(first);
+}
+
+
+struct car* clear_train(struct car* first, const char* target)
+{
+    if(first == NULL)
+    {
+        return NULL;
+    }
+    if(first->next == NULL)
+    {
+        if(strcmp(first->value, target))
+        {
+            free(first);
+            return NULL;
+        }
+        else
+        {
+            return first;
+        }
+    }
+    struct car* prev = first;
+    while (prev->next->next != NULL)
+    {
+        if(strcmp(prev->value, target))
+        {
+            struct car* third = prev->next->next;
+            free(prev->next);
+            prev->next = third;
+            return first;
+        }
+        prev = prev->next;
+    }
+	return first;
+}
+

cv4/a_train.h

@@ -0,0 +1,51 @@
+#ifndef TRAIN_H
+#define TRAIN_H
+#define SIZE 100
+
+/**
+ * Jeden vozen vlaku
+ */
+struct car {
+    /**
+     * Nazov cielovej  stanice
+     */
+    char value[SIZE];
+    /**
+     * Smenik na dalsi vozen
+     */
+    struct car* next;
+};
+
+/**
+ * Prida vozen na koniec vlaku.
+ *
+ * @arg nazov cielovej stanice, ktory sa ma priradit novemu voznu.
+ * @return smernik na zaciatok vlaku.
+ */
+struct car* add_car(struct car* first,const char* target);
+
+
+/**
+ * Vypise vsetky vozne vo vlaku
+ *
+ * @arg smernik na prvy vozen
+ */
+void print_train(struct car* first);
+
+/**
+ * Zrusenie vsetkych voznov vo vlaku.
+ * @arg smernik na prvy vozen
+ */
+void cancel_train(struct car* first);
+
+/**
+ * Vyradenie vsetkych voznov, ktorych cielova stanica je target
+ *
+ * @arg smernik na prvy vozen
+ * @arg cielova stanica, ktora sa ma vyradit z vlaku.
+ * @return smernik na novy prvy vozen
+ *
+ */
+struct car* clear_train(struct car* first,const char* target);
+
+#endif // TRAIN_H

cv4/main.c

@@ -0,0 +1,32 @@
+#include "a_train.h"
+#include <stdio.h>
+#include <string.h>
+
+int main()
+{
+    char buf[50];
+    struct car* train = NULL;
+    memset(buf, 0, 50);
+    printf("Zadajte zoznam cieľových staníc.\nZoznam zakončite prázdnym riadkom.\n");
+    while (fgets(buf, 50, stdin) != NULL)
+    {
+        if(buf[0] == '\n')
+        {
+            break;
+        }
+        buf[strcspn(buf, "\n")] = '\0';
+        train = add_car(train,buf);
+    }
+
+    print_train(train);
+
+    printf("Zadajte stanicu, ktorá sa má vyradiť:\n");
+    scanf("%s", buf);
+    clear_train(train,buf);
+
+    print_train(train);
+
+    cancel_train(train);
+
+    return 0;
+}