为什么出这样的结果呢？百思不得其解
源程序：
#include <stdlib.h>
#include <iostream.h>
#include <iomanip.h>
#include <string.h>
#include <stdio.h>
typedef struct
{
int weight;
int parent,lchild,rchild;
char ch;
}HTNode , *htree;
void CreatTree(htree *ht , int *f,int x)
{
int i;
int j=0;
for(i=0;i <x;i++)
{
cout < < "i = " < < i < <endl;
cout < < "j = " < < j < <endl;
cout < < "f[ " < <j < < "] 1 = " < < f[j] < <endl;
(*ht)[i].weight = f[j];
cout < < "weight = " < < (*ht)[i].weight < <endl;
j++;
}
}
main(){
int f[16] = {1,2,3,4,5,16,17,8,9,10,11,12,13,14,15,16};
int x = 16;
htree HT;
CreatTree(&HT,f,x);
return 0;
}
输出结果：
i =0
j =0
f[0] 1 =1
weight =1
i =1
j =1
f[1] 1 =2
weight =2
i =2
j =2
f[2] 1 =3
weight =3
i =3
j =3
f[3] 1 =4
weight =4
i =4
j =4
f[4] 1 =5
weight =5
i =5
j =5
f[5] 1 =16
weight =16
i =6
j =6
f[6] 1 =1
weight =1
i =7
j =7
f[7] 1 =8
weight =8
i =8
j =8
f[8] 1 =9
weight =9
i =9
j =9
f[9] 1 =10
weight =10
i =10
j =10
f[10] 1 =11
weight =11
i =11
j =11
f[11] 1 =2
weight =2
i =12
j =12
f[12] 1 =13
weight =13
i =13
j =13
f[13] 1 =14
weight =14
i =14
j =14
f[14] 1 =15
weight =15
i =15
j =15
f[15] 1 =16
weight =16
第七个和第十二个为什么不是17和12呢？
[解决办法]
//应该是这样写的吧
#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <string>
#include <cstdio>
using namespace std;
typedef struct
{
int weight;
int parent, lchild, rchild;
char ch;
}HTNode , *htree;
void CreatTree(htree *ht , int *f, int x)
{
int i;
int j=0;
*ht = new HTNode[x];//这里应该先在堆中分配一段空间
for(i=0; i <x; i++)
{
cout < < "i = " < < i < <endl;
cout < < "j = " < < j < <endl;
cout < < "f[ " < <j < < "] 1 = " < < f[j] < <endl;
//没有上面那一个分配空间语句，你这下面的操作都是
//在未分配的内存上进行读写操作，会早成未定义的错误
//即不知道什么时候就会出错，这就是你的程序出错的原因
(*ht)[i].weight = f[j];
cout < < "weight = " < <(*ht)[i].weight < <endl;
j++;
}
}
int main(void)
{
int f[16] = {1, 2, 3, 4, 5, 16, 17, 8, 9, 10, 11, 12, 13, 14, 15, 16};
int x = 16;
htree HT;
CreatTree(&HT, f, x);
delete [] HT; // 这里要删除
return 0;
}
[解决办法]
在VC上运行都运行不了,停在(*ht)[i].weight = f[j];上面了,因为ht都没有分配内存的...
