added part of todays exercises

.gitignore

 a.out
 .nfs*
+*.o
+main

Lezione 6-7/1/Makefile

+CC = cc
+CLFAGS = -g -Wall -Wextra
+objects = list.o person.o input.o main.o
+
+%.o : %.c
+	$(CC) -c $(CFLAGS) $< -o $@
+all: $(objects)
+	$(CC) -o main $(objects)
+clean:
+	rm main $(objects)

Lezione 6-7/1/input.c

+#include "input.h"
+#include <stdio.h>
+#include <string.h>
+
+char *fgets_strip(char *s, int size, FILE *stream) {
+    char *ret = fgets(s, size, stream);
+    s[strcspn(s, "\n")] = 0;
+    return ret;
+}

Lezione 6-7/1/input.h

+#ifndef INPUT_H
+#define INPUT_H
+
+#include <stdio.h>
+
+char *fgets_strip(char *s, int size, FILE *stream);
+
+#endif

Lezione 6-7/1/input.txt

+Mario Rossi 10
+Marco Bianchi 20
+Mirko Verdi 30
+END

Lezione 6-7/1/list.c

+#include "list.h"
+#include <stdlib.h>
+
+Link list_new_raw(void) {
+    return malloc(sizeof(ListHead));
+}
+
+Link list_new(Data data) {
+    Link ret = list_new_raw();
+    ret->data = data;
+    ret->next = NULL;
+    return ret;
+}
+
+Link list_input(FILE *f, int (*input) (FILE *, Data *)) {
+    Data data;
+
+    if (input(f, &data)) {
+        Link head = list_new(data);
+        head->next = list_input(f, input);
+        return head;
+    }
+
+    return NULL;
+}
+
+void list_print(Link head, void (*print) (Data *)) {
+    if (head) {
+        print(&head->data);
+        list_print(head->next, print);
+    }
+}

Lezione 6-7/1/list.h

+#ifndef LIST_H
+#define LIST_H
+
+#include "person.h"
+#include <stdio.h>
+
+typedef Person Data;
+
+typedef struct ListHead {
+    struct ListHead *next;
+    Data data;
+} ListHead;
+
+typedef ListHead *Link;
+
+Link list_new_(void);
+Link list_input(FILE *f, int (*input) (FILE *, Data *));
+void list_print(Link head, void (*print) (Data *));
+
+#endif

Lezione 6-7/1/main.c

+#include <stdio.h>
+#include <stdlib.h>
+#include "list.h"
+#include "person.h"
+
+int main(int argc, char *argv[]) {
+    if (argc != 2) {
+        return EXIT_FAILURE;
+    }
+    FILE *f;
+    if (!(f = fopen(argv[1], "r"))) {
+        return EXIT_FAILURE;
+    }
+
+    Link head = list_input(f, person_read);
+    fclose(f);
+
+    list_print(head, person_print);
+}

Lezione 6-7/1/person.c

+#include "person.h"
+#include "util.h"
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+int person_parse(char *s, Person *person) {
+    char format[4 + 1 + 4 + 1 + 2 + 1];
+    assert((size_t)snprintf(
+        format,
+        ARR_LEN(format),
+        "%%%zus %%%zus %%u",
+        ARR_LEN(person->first_name),
+        ARR_LEN(person->last_name)
+    ) < ARR_LEN(format));
+
+    return sscanf(
+        s,
+        format,
+        person->first_name,
+        person->last_name,
+        &person->age
+    ) < 3 ? -1 : 0;
+}
+
+int person_read(FILE *f, Person *person) {
+    char buf[256];
+    fgets_strip(buf, ARR_LEN(buf), f);
+
+    if (strncmp(buf, FILE_END, ARR_LEN(FILE_END)) == 0) {
+        return 0;
+    }
+    return person_parse(buf, person) < 0 ? 0 : 1;
+}
+
+void person_print(Person *person) {
+    printf(
+        "nome: %s, cognome: %s, eta': %u\n",
+        person->first_name,
+        person->last_name,
+        person->age
+    );
+}

Lezione 6-7/1/person.h

+#ifndef PERSON_H
+#define PERSON_H
+
+#include "input.h"
+#include <stdio.h>
+
+#define FILE_END "END"
+
+typedef struct {
+    char first_name[64];
+    char last_name[64];
+    unsigned int age;
+} Person;
+
+
+int person_parse(char *s, Person *person);
+int person_read(FILE *f, Person *person);
+void person_print(Person *person);
+
+#endif

Lezione 6-7/1/util.h

+#ifndef UTIL_H
+#define UTIL_H
+
+#define ARR_LEN(arr) (sizeof(arr) / sizeof(*arr))
+
+#endif

Lezione 6-7/2/Makefile

+CC = cc
+CLFAGS = -g -Wall -Wextra
+objects = list.o person.o input.o main.o
+
+%.o : %.c
+	$(CC) -c $(CFLAGS) $< -o $@
+all: $(objects)
+	$(CC) -o main $(objects)
+run: all
+	./main input.txt
+clean:
+	rm main $(objects)

Lezione 6-7/2/input.c

+#include "input.h"
+#include <stdio.h>
+#include <string.h>
+
+char *fgets_strip(char *s, int size, FILE *stream) {
+    char *ret = fgets(s, size, stream);
+    s[strcspn(s, "\n")] = 0;
+    return ret;
+}
+
+void flush_stdin(void) {
+    int c;
+    while ((c = getchar()) != '\n' && c != EOF);
+}

Lezione 6-7/2/input.h

+#ifndef INPUT_H
+#define INPUT_H
+
+#include <stdio.h>
+
+char *fgets_strip(char *s, int size, FILE *stream);
+void flush_stdin(void);
+
+
+#endif

Lezione 6-7/2/input.txt

+Mario Rossi 10
+Marco Bianchi 20
+Mirko Verdi 30
+END

Lezione 6-7/2/list.c

+#include "list.h"
+#include <stdlib.h>
+
+Link list_new_raw(void) {
+    return malloc(sizeof(ListHead));
+}
+
+Link list_new(Data data) {
+    Link ret = list_new_raw();
+    ret->data = data;
+    ret->next = NULL;
+    return ret;
+}
+
+Link list_input(FILE *f, int (*input) (FILE *, Data *)) {
+    Data data;
+
+    if (input(f, &data)) {
+        Link head = list_new(data);
+        head->next = list_input(f, input);
+        return head;
+    }
+
+    return NULL;
+}
+
+void list_print(Link head, void (*print) (Data *)) {
+    if (head) {
+        print(&head->data);
+        list_print(head->next, print);
+    }
+}
+
+Link list_nth(Link head, size_t n) {
+    if (head) {
+        return n > 0 ? list_nth(head->next, n - 1) : head;
+    }
+    return NULL;
+}
+
+Link list_find(Link head, int (*compare) (Data *, Data *), Data *key) {
+    if (head) {
+        if (compare(&head->data, key)) {
+            return head;
+        }
+        return list_find(head->next, compare, key);
+    }
+    return NULL;
+}

Lezione 6-7/2/list.h

+#ifndef LIST_H
+#define LIST_H
+
+#include "person.h"
+#include <stdio.h>
+
+typedef Person Data;
+
+typedef struct ListHead {
+    struct ListHead *next;
+    Data data;
+} ListHead;
+
+typedef ListHead *Link;
+
+Link list_new_(void);
+Link list_input(FILE *f, int (*input) (FILE *, Data *));
+void list_print(Link head, void (*print) (Data *));
+Link list_find(Link head, int (*compare) (Data *, Data *), Data *key);
+Link list_nth(Link head, size_t n);
+
+#endif

Lezione 6-7/2/main.c

+#include <stdio.h>
+#include <stdlib.h>
+#include "list.h"
+#include "person.h"
+#include "input.h"
+#include "util.h"
+
+#define MESSAGE_NOT_FOUND "persona non trovata"
+
+int main(int argc, char *argv[]) {
+    if (argc != 2) {
+        return EXIT_FAILURE;
+    }
+    FILE *f;
+    if (!(f = fopen(argv[1], "r"))) {
+        return EXIT_FAILURE;
+    }
+
+    Link list = list_input(f, person_read);
+    fclose(f);
+
+    puts("ricerca per [c]ognome o [p]osizione?");
+    int choice = getchar();
+    flush_stdin();
+
+    Link found;
+    switch (choice) {
+        case 'c': {
+            puts("inserire cognome");
+            Person key;
+            fgets_strip(key.last_name, ARR_LEN(key.last_name), stdin);
+            found = list_find(list, person_is_related, &key);
+            break;
+        }
+        case 'p': {
+            puts("inserire posizione");
+            size_t n;
+            scanf("%zu", &n);
+            found = list_nth(list, n);
+            break;
+        }
+        default:
+            return EXIT_FAILURE;
+            break;
+    }
+
+    if (found) {
+        person_print(&found->data);
+    } else {
+        fputs(MESSAGE_NOT_FOUND "\n", stderr);
+    }
+}

Lezione 6-7/2/person.c

+#include "person.h"
+#include "util.h"
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+int person_parse(char *s, Person *person) {
+    char format[4 + 1 + 4 + 1 + 2 + 1];
+    assert((size_t)snprintf(
+        format,
+        ARR_LEN(format),
+        "%%%zus %%%zus %%u",
+        ARR_LEN(person->first_name),
+        ARR_LEN(person->last_name)
+    ) < ARR_LEN(format));
+
+    return sscanf(
+        s,
+        format,
+        person->first_name,
+        person->last_name,
+        &person->age
+    ) < 3 ? -1 : 0;
+}
+
+int person_read(FILE *f, Person *person) {
+    char buf[256];
+    fgets_strip(buf, ARR_LEN(buf), f);
+
+    if (strncmp(buf, FILE_END, ARR_LEN(FILE_END)) == 0) {
+        return 0;
+    }
+    return person_parse(buf, person) < 0 ? 0 : 1;
+}
+
+void person_print(Person *person) {
+    printf(
+        "nome: %s, cognome: %s, eta': %u\n",
+        person->first_name,
+        person->last_name,
+        person->age
+    );
+}
+
+int person_is_related(Person *p1, Person *p2) {
+    return strcmp(p1->last_name, p2->last_name) == 0;
+}

Lezione 6-7/2/person.h

+#ifndef PERSON_H
+#define PERSON_H
+
+#include "input.h"
+#include <stdio.h>
+
+#define FILE_END "END"
+
+typedef struct {
+    char first_name[64];
+    char last_name[64];
+    unsigned int age;
+} Person;
+
+
+int person_parse(char *s, Person *person);
+int person_read(FILE *f, Person *person);
+void person_print(Person *person);
+int person_is_related(Person *p1, Person *p2);
+
+#endif