c语言 - 为什么我在结构上遇到 SIGSEGV 错误？

Question

我的程序有问题：在数据采集过程中，当我输入第二个数据时，程序停止运行并发生SIGSEGV错误（p.s.我正在使用结构）。

代码如下：

#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("%dn", &tab_dip[i].codice);
     }while(tab_dip[i].codice<0);
     printf("Inserire il nome del dipendente: ");
     scanf("%sn", tab_dip[i].nom);
     printf("Inserire il cognome del dipendente: ");
     scanf("%sn", tab_dip[i].cogn);
     do{
         printf("Inserire il numero di sinistri trattati: ");
         scanf("%dn", &tab_dip[i].n_sin_trat);
     }while(tab_dip[i].n_sin_trat<0);
     do{
         printf("Inerire il numero di sinistri conclusi");
         scanf("%dn", &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("%dn", &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("%dn",tab_dip[i].codice);
     printf("%sn",tab_dip[i].nom);
     sin_no_conc1=tab_dip[i].n_sin_trat-tab_dip[i].n_sin_conc;
     printf("%dn", sin_no_conc1);
     comp_tot=sin_no_conc1*tab_dip[i].compenso;
     printf("%dn", comp_tot);
 }while(i<n_dip);
  return 0;
}

编辑

现在输入阶段有效，但是当我尝试使用气泡排序对数据进行排序时（我必须使用气泡排序），程序停止工作。代码如下：

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

这更适合作为代码审查问题：

#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("%dn",tab_dip[i].codice);
        printf("%sn",tab_dip[i].nom);
        sin_no_conc1=tab_dip[i].n_sin_trat-tab_dip[i].n_sin_conc;
        printf("%dn", sin_no_conc1);
        comp_tot=sin_no_conc1*tab_dip[i].compenso;
        printf("%dn", comp_tot);
    }
    return 0;
}