Question

C++，数据结构 请问，为什么编译没有出，但是运行就会出错呢？

#define MaxSize 50
#include <iostream.h>
#include <stdlib.h>
#include <iomanip.h>
typedef char ElemType;
typedef struct
{ElemType data[MaxSize];
int length;
}SqList;
void BuildList(SqList *L,ElemType a[],int n)
{
int i=0;
L=new SqList;
for (;i<n;i++)
L->data[i]=a[i];
L->length=i;
}
//基本算法
void InitList(SqList *L)
{
L=new SqList;
L->length=0;
}
void DetroyList (SqList *&L)
{
free (L);
}
int EmptyList (SqList *L)
{
if(L->length) return 1;
return 0;
}
void DisplayList(SqList *L)
{
int i;
for (i=0;i<L->length;i++)
{
cout<<setw(8)<<L->data[i];
if (i%5==0) cout<<endl;
}
}
void GetElem(SqList *L,ElemType n)
{
if(n<=L->length)
{n--;
cout<<L->data[n]<<endl;}
else cout<<"超出范围！"<<endl;
}
void LocateElem(SqList *L,int n)
{
int i;
for (i=0;i<L->length;i++)
{
if (L->data[n]==n) break;
}
i++;
if (i<=L->length)
cout<<"该元素为："<<i<<endl;
else cout<<"没有找到该元素！"<<endl;
}
void InsertElem (SqList *&L,int n,ElemType e)
{
if((n<=L->length+1)&&n<=MaxSize)
{
n--;
int i;
for (i=L->length;i!=n;i--)
L->data[i]=L->data[i-1];
L->data[i]=e;
}
else cout<<"操作失败，超出范围！"<<endl;
}
void DeleteElem (SqList *&L,int n)
{
if(n<=L->length)
{ int i;
for (i=0;i!=L->length-1;i++)
L->data[i]=L->data[i+1];
}
else cout<<"操作失败，超出范围！"<<endl;
}

void main()
{
SqList *L;
int n=5;
ElemType a[MaxSize]={'a','b','c','d','e'};
BuildList(L,a,n);
DisplayList (L);
cout<<"列表长度为："<<L->length<<endl;
if (EmptyList (L)) cout<<"非空表"<<endl;
else cout<<"空表"<<endl;
GetElem(L,3);
LocateElem(L,'a');
InsertElem(L,4,'f');
DisplayList(L);
DeleteElem(L,3);
DisplayList(L);
}

Answer 1

错误一堆啊。
void BuildList(SqList **L,ElemType a[],int n) //这样传递。SqList **L

#define MaxSize 50
#include <iostream>
#include <stdlib.h>
#include <iomanip>
using namespace std;
typedef char ElemType;
typedef struct
{ElemType data[MaxSize];
int length;
}SqList;
void BuildList(SqList **L,ElemType a[],int n)
{
int i=0;
*L=new SqList;
for (;i<n;i++)
(*L)->data[i]=a[i];
(*L)->length=i;
}
//基本算法
void InitList(SqList *L)
{
L=new SqList;
L->length=0;
}
void DetroyList (SqList *&L)
{
free (L);
}
int EmptyList (SqList *L)
{
if(L->length) return 1;
return 0;
}
void DisplayList(SqList *L)
{
int i;
for (i=0;i<L->length;i++)
{
cout<<setw(8)<<L->data[i];
if (i%5==0) cout<<endl;
}
}
void GetElem(SqList *L,ElemType n)
{
if(n<=L->length)
{n--;
cout<<L->data[n]<<endl;}
else cout<<"超出范围！"<<endl;
}
void LocateElem(SqList *L,int n)
{
int i;
for (i=0;i<L->length;i++)
{
if (L->data[n]==n) break;
}
i++;
if (i<=L->length)
cout<<"该元素为："<<i<<endl;
else cout<<"没有找到该元素！"<<endl;
}
void InsertElem (SqList *&L,int n,ElemType e)
{
if((n<=L->length+1)&&n<=MaxSize)
{
n--;
int i;
for (i=L->length;i!=n;i--)
L->data[i]=L->data[i-1];
L->data[i]=e;
}
else cout<<"操作失败，超出范围！"<<endl;
}
void DeleteElem (SqList *&L,int n)
{
if(n<=L->length)
{ int i;
for (i=0;i!=L->length-1;i++)
L->data[i]=L->data[i+1];
}
else cout<<"操作失败，超出范围！"<<endl;
}

void main()
{
SqList *L=NULL;
int n=5;
ElemType a[MaxSize]={'a','b','c','d','e'};
BuildList(&L,a,n);
DisplayList (L);
cout<<"列表长度为："<<L->length<<endl;
if (EmptyList (L)) cout<<"非空表"<<endl;
else cout<<"空表"<<endl;
GetElem(L,3);
LocateElem(L,'a');
InsertElem(L,4,'f');
DisplayList(L);
DeleteElem(L,3);
DisplayList(L);
}

追问

void BuildList(SqList **L,ElemType a[],int n) //这样传递。SqList **L

指向指针的指针？为什么要这样呢？
可以加QQ问你吗？

追答

理解值传递和地址传递。
33563743

Answer 2

void LocateElem(SqList *L,int n)
{
int i;
for (i=0;i<L->length;i++)
{
if (L->data[n]==n) break; //改为L->data[i]==n
}
i++;
if (i<=L->length)
cout<<"该元素为："<<i<<endl;
else cout<<"没有找到该元素！"<<endl;
}

Answer 3

运行时出了什么错，有没有图片