Pourquoi je reçois une erreur SIGSEGV avec des structures?

Question

J'ai un problème avec mon programme: lors de l'acquisition de données, lorsque j'entre en entrée les secondes données, le programme s'arrête et une erreur SIGSEGV se produit (p.s. je travaille avec des structures).

Voici le code:

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

typedef struct{ 
int codice; 
char nom[20]; 
char cogn[20]; 
int n_sin_trat; 
int n_sin_conc; 
int compenso; 
} Dip; 


int main() 
{ 
    int n_dip; 
    int i,p,sin_no_conc1, sin_no_conc2, comp_tot; 
    int scambio; 
    do{ 
    printf("Inserire numero dipendenti: "); 
    scanf("%d", &n_dip); 
    }while(n_dip<=0); 
    Dip tab_dip[n_dip]; 
    Dip temp; 
    do{ 
     i=i+1; 
     do{ 
     printf("Inserire il codice del dipendente: "); 
     scanf("%d\n", &tab_dip[i].codice); 
    }while(tab_dip[i].codice<0); 
    printf("Inserire il nome del dipendente: "); 
    scanf("%s\n", tab_dip[i].nom); 
    printf("Inserire il cognome del dipendente: "); 
    scanf("%s\n", tab_dip[i].cogn); 
    do{ 
     printf("Inserire il numero di sinistri trattati: "); 
     scanf("%d\n", &tab_dip[i].n_sin_trat); 
    }while(tab_dip[i].n_sin_trat<0); 
    do{ 
     printf("Inerire il numero di sinistri conclusi"); 
     scanf("%d\n", &tab_dip[i].n_sin_conc); 
    }while(tab_dip[i].n_sin_conc>=tab_dip[i].n_sin_trat); 
    do{ 
     printf("Immettere il compenso per sinistro"); 
     scanf("%d\n", &tab_dip[i].compenso); 
    }while(tab_dip[i].compenso>0); 
    }while(i<n_dip); 

    p=n_dip; 
    do{ 
    scambio=0; 
    i=0; 
    do{ 
     i=i+1; 
     sin_no_conc1=tab_dip[i].n_sin_trat-tab_dip[i].n_sin_conc; 
     sin_no_conc2=tab_dip[i+1].n_sin_trat-tab_dip[i+1].n_sin_conc; 
     if(sin_no_conc1>sin_no_conc2){ 
      temp=tab_dip[i]; 
      tab_dip[i]=tab_dip[i+1]; 
      tab_dip[i+1]=temp; 
      scambio=1; 
     } 
    }while(i<p-1); 
    p=p-1; 
}while(scambio==0); 

i=0; 
do{ 
    i=i+1; 
    printf("%d\n",tab_dip[i].codice); 
    printf("%s\n",tab_dip[i].nom); 
    sin_no_conc1=tab_dip[i].n_sin_trat-tab_dip[i].n_sin_conc; 
    printf("%d\n", sin_no_conc1); 
    comp_tot=sin_no_conc1*tab_dip[i].compenso; 
    printf("%d\n", comp_tot); 
}while(i<n_dip); 

    return 0; 
} 

EDIT

Maintenant, les travaux de la phase d'entrée, mais lorsque je tente d'obtenir des données avec une sorte de bulle (je suis obligé d'utiliser le tri à bulles), le programme cesse de fonctionner. Voici le code:

for (p = n_dip, scambio = 0; scambio==0; p--) { 
    scambio=0; 
    for (i = 0; i < p - 1; i++) { 
     sin_no_conc1=tab_dip[i].n_sin_trat-tab_dip[i].n_sin_conc; 
     sin_no_conc2=tab_dip[i+1].n_sin_trat-tab_dip[i+1].n_sin_conc; 
     if(sin_no_conc1>sin_no_conc2){ 
      temp=tab_dip[i]; 
      tab_dip[i]=tab_dip[i+1]; 
      tab_dip[i+1]=temp; 
      scambio=1; 
     } 
    } 
} 

Answer 1

C'est un peu mieux comme une question de révision du code:

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

// Note: Indent and use spaces around punctuation 
typedef struct { 
    int codice; 
    char nom[20]; 
    char cogn[20]; 
    int n_sin_trat; 
    int n_sin_conc; 
    int compenso; 
} Dip; 

int main() 
{ 
    int n_dip; 
    int i,p,sin_no_conc1, sin_no_conc2, comp_tot; 
    int scambio; 
    do { 
     printf("Inserire numero dipendenti: "); 
     // Note: Check the result of scanf 
     // Note: Scanf doesn't change any variables if it didn't 
     // read them. You've likely been lucky that you randomly had 
     // negative values in these uninitialized variables. 
    } while(scanf("%d", &n_dip) != 1 || n_dip < 0); 

    // Note: Use vertical space to separate sections 
    // c99 dynamic array size 
    Dip tab_dip[n_dip]; 
    Dip temp; 

    // Previously, this code started with do { i = i + 1; 
    // Which would cause an off-by-one error in the code leading to 
    // a crash. C arrays are indexed from 0, so an array of n_dip 
    // values contains tab_dip[0] ... tab_dip[n_dip - 1] 
    // 
    // Your code would start the iteration, then increment i at the top 
    // which even if i was initialized, would have indexed past the 
    // last array element. By convention, code usually increments 
    // indexes at the end. Note that the for loop already does that 
    // and reminds one to initialize the loop variable. 
    for (i = 0; i < n_dip; i++) { 
     do { 
      printf("Inserire il codice del dipendente: "); 
      // Again, check the result of scanf and ensure that it 
      // read a value before checking the value 
     } while(scanf("%d", &tab_dip[i].codice) != 1 || tab_dip[i].codice < 0); 

     printf("Inserire il nome del dipendente: "); 
     scanf("%s", tab_dip[i].nom); 
     printf("Inserire il cognome del dipendente: "); 
     scanf("%s", tab_dip[i].cogn); 

     do { 
      printf("Inserire il numero di sinistri trattati: "); 
     } while(scanf("%d", &tab_dip[i].n_sin_trat) != 1 || tab_dip[i].n_sin_trat < 0); 

     do { 
      printf("Inerire il numero di sinistri conclusi"); 
     } while(scanf("%d", &tab_dip[i].n_sin_conc) != 1 || tab_dip[i].n_sin_conc >= tab_dip[i].n_sin_trat); 

     do{ 
      printf("Immettere il compenso per sinistro"); 
     }while(scanf("%d", &tab_dip[i].compenso) != 1 || tab_dip[i].compenso > 0); 
    } 

    // The comma operator in C can be used to do multiple 
    // initializations or increments in the for loop prelude. 
    // Note that the condition can be any condition. Here, we're 
    // emulating do-while by satisfying the condition on the first 
    // pass. 
    for (p = n_dip, scambio = 0; scambio==0; p--) { 
     scambio=0; 
     for (i = 0; i < p - 1; i++) { 
      sin_no_conc1=tab_dip[i].n_sin_trat-tab_dip[i].n_sin_conc; 
      sin_no_conc2=tab_dip[i+1].n_sin_trat-tab_dip[i+1].n_sin_conc; 
      if(sin_no_conc1>sin_no_conc2){ 
       temp=tab_dip[i]; 
       tab_dip[i]=tab_dip[i+1]; 
       tab_dip[i+1]=temp; 
       scambio=1; 
      } 
     } 
    } 

    for (i = 0; i < n_dip; i++) { 
     printf("%d\n",tab_dip[i].codice); 
     printf("%s\n",tab_dip[i].nom); 
     sin_no_conc1=tab_dip[i].n_sin_trat-tab_dip[i].n_sin_conc; 
     printf("%d\n", sin_no_conc1); 
     comp_tot=sin_no_conc1*tab_dip[i].compenso; 
     printf("%d\n", comp_tot); 
    } 

    return 0; 
}