Thread: Particular problem with a for loop

I have a particular problem with a for loop. This should write to a text file of the structures belonging to an ordered list in order to get a table.
Here is the code:

Code:

struct comp
{
    int code;
    char name[27];
    char des[52];
    int disp;
    struct comp *n;
};

struct comp *comps = 0, *p;

FILE *fw = fopen("miofile.txt", "w");

for(p = comps; p; p = p->n)
{
s1 = ((((float)(25 - strlen(p->name))) + 0.5) / 2);
s2 = ((((float)(25 - strlen(p->name))) - 0.5) / 2);
s3 = ((((float)(52 - strlen(p->des))) + 0.5) / 2);
s4 = ((((float)(52 - strlen(p->des))) - 0.5) / 2) - 1;
fprintf(fw, "|  %09.9i  ", p->code);
fprintf(fw, "| %*s%.25s%*s ", s1, " ", p->name, s2, " ");
fprintf(fw, "| %*s%.50s%*s ", s3, " ", p->des, s4, " "); fprintf(fw, "|    %09.9i    |\n", p->disp);
}

fclose(fw);

But the cycle continues indefinitely, and the output file size becomes huge, although there are written only a few structures (tested with notepad ++). The strange thing is that if I try to visualize the structures on the screen, the same cycle adapted to the purpose and ends properly and if I try to write to a file only the code and the availability of components, leaving out the name and description, in this If the loop ends correctly.

Here is the code:

Code:

for(p = comps; p; p = p->n)
{
s1 = ((((float)(25 - strlen(p->name))) + 0.5) / 2);
s2 = ((((float)(25 - strlen(p->name))) - 0.5) / 2);
s3 = ((((float)(52 - strlen(p->des))) + 0.5) / 2);
s4 = ((((float)(52 - strlen(p->des))) - 0.5) / 2) - 1;
fprintf(fw, "|  %09.9i  ", p->code);
// fprintf(fw, "| %*s%.25s%*s ", s1, " ", p->name, s2, " "); not compiled
// fprintf(fw, "| %*s%.50s%*s ", s3, " ", p->des, s4, " "); not compiled
fprintf(fw, "|    %09.9i    |\n", p->disp);
}

Any suggestion?

Where do you allocate memory for your structs?

Here is the complete code of program:

Code:

#include <stdlib.h>
#include <stdio.h>

void insert(void);
void visualize(void);
void save(void);
int llinea(char *str, int n);

struct comp
{
    int code;
    char name[27];
    char des[52];
    int disp;
    struct comp *n;
};

struct comp *comps = 0;

int main()
{
    int c;
    for(;;)
    {
        fputs("________________________________________________________________________________\n", stdout);
        fputs("Database componenti ©2011\n\n", stderr);

        fputs("1 - Inserisci componente nel database\n\n", stderr);
        fputs("2 - Visualizza il database\n\n", stderr);
        fputs("3 - Salva database\n\n", stderr);
        fputs("4 - Esci dal programma\n", stderr);
        fputs("________________________________________________________________________________\n", stderr);
        fputs("Inserisci il codice corrispondente all'operazione: ", stderr);

        fflush(stdin);
        scanf("%i", &c);

        if(c == 1)
        {
            inserisci();
        }
        else if(c == 2)
        {
            visualizza();
        }
        else if(c == 3)
        {
            salva();
        }
        else if(c == 4)
        {
            return 0;
        }
        else
        {
            fputs("\nIl codice inserito non è valido.\n\n------------------------Premere un tasto per continuare---------------------\n", stderr);
            fflush(stdin);
            getchar();
            fputs("\n\n", stderr);
        }
fputs("\n------------------------Premere un tasto per continuare---------------------\n", stderr);
            fflush(stdin);
            getchar();
            fputs("\n\n", stderr);

    }
}

void insert()
{
    struct comp *p, *c, *nn = calloc(1, sizeof(struct comp));

    if(!nn)
    {
        fputs("Memoria piena. Impossibile aggiungere il componente.\n", stderr);
    }

    fputs("\nInserisci il codice del componente (max. 99999999): ", stderr);
    fflush(stdin);
    scanf("%9i", &nn->code);

    for(c = comps, p = 0; c && nn->code > c->code; p = c, c = c->n);
    if(c && (nn->code == c->code))
    {
        fputs("Il componente esiste gia'. Impossibile aggiungere il componente.\n", stderr);
        return;
    }

    fputs("Inserisci il nome del componente: ", stderr);
    llinea(nn->name, 25);
    fputs("Inserisci la descrizione del componente: ", stderr);
    llinea(nn->des, 100);
    fputs("Inserisci la disponibilita' del componente: ", stderr);
    fflush(stdin);
    scanf("%i", &nn->disp);

    nn->n = c;
    if(!p)
    {
        comps = nn;
    }
    else
    {
        p->n = nn;
    }
}

void visualize()
{
    struct comp *p;
    for(p = comps; p; p = p->n)
        {
            fprintf(stderr, "\nCodice del componente:           %i\n", p->code);
            fprintf(stderr, "Nome del componente:             %s\n", p->name);
            fprintf(stderr, "Descrizione del componente:      %s\n", p->des);
            fprintf(stderr, "Disponibilita' del componente:   %i\n\n", p->disp);
        }
}

void save()
{
    FILE *fw;
    struct comp *p;

    if((fw = fopen("C:\\Users\\Utente\\Desktop\\prova.txt", "w")) != NULL)
    {
     int s1;
     int s2;
     int s3;
     int s4;

            fputs("\n|    CODICE   |           NOME           |                     DESCRIZIONE                    |  DISPONIBILITA' |\n", fw);
            fputs("\n|             |                          |                                                    |                 |\n", fw);

            for(p = comps; p; p = p->n)
            {
                s1 = ((((float)(25 - strlen(p->name))) + 0.5) / 2);
                s2 = ((((float)(25 - strlen(p->name))) - 0.5) / 2);
                s3 = ((((float)(52 - strlen(p->des))) + 0.5) / 2);
                s4 = ((((float)(52 - strlen(p->des))) - 0.5) / 2) - 1;
                fprintf(fw, "|  %09.9i  ", p->code);
                fprintf(fw, "| %*s%.25s%*s ", s1, " ", p->name, s2, " ");
                fprintf(fw, "| %*s%.50s%*s ", s3, " ", p->des, s4, " ");
                fprintf(fw, "|    %09.9i    |\n", p->disp);
            }
    }
    fclose(fw);
}

int llinea(char *str, int n)
{
    int c, i = 0;

    fflush(stdin);
    while(isspace(c = getc(stdin)));

    while(c != '\n')
    {
        if(i < n)
        {
            str[i++] = c;
        }
        c = getc(stdin);
    }

    if(n == i)
    {
        str[i++] = (int) "*";
    }
    str[i] = '\0';

    return i;
}

well, it doesn't compile...
I don't know where you get the functions inserisci(), visualizza() from.
It would also help if it where english...