我使用此代码收到了分段错误错误：
以下是标题：
using namespace std;
class Dynamic_array {
public:
Dynamic_array();
Dynamic_array(Dynamic_array &);
Dynamic_array &operator=(Dynamic_array &);
~Dynamic_array();
void print_state(void);
int get_size(void);
int& operator[](int);
void insert(int, int);
void insert(Dynamic_array &, int);
void remove(int);
void remove(int, int);
class Subscript_range_exception {
};
private:
enum {
BLOCK_SIZE = 5,
};
class Block {
public:
int size;
int a[BLOCK_SIZE];
Block* next_p;
};
class Block_position {
public:
Block* block_p;
Block* pre_block_p;
int i;
};
Block_position find_block(int i);
void insert_blocks(Block *, Block *);
void remove_blocks(Block *, Block *, Block *);
Block * copy_blocks(Block *);
void delete_blocks(Block *);
int size;
Block* head_p;
};
我的其余代码。当块的大小为1时，它会起作用。当大小大于1时，它会抛出分段错误。
#include <iostream> //-
#include <string.h> //-
#include "dynamic_array.h" //-
//-
using namespace std; //-
//-
// ********** public functions ********** //-
int main(){
Dynamic_array d;
d.insert(1,0);
d.insert(3,1);
d.insert(5,2);
d.insert(7,3);
d.insert(9,4);
d.insert(11,5);
d.print_state();
cout << "********** remove(int i)" << endl;
cout << "********** case 1: range error" << endl;
try {
d.remove(-1);
} catch (Dynamic_array::Subscript_range_exception) {
cout << "exception caught at -1" << endl;
}
try {
d.remove(6);
} catch (Dynamic_array::Subscript_range_exception) {
cout << "exception caught at 6" << endl;
}
cout << "********** case 2: block size == 1" << endl;
d.remove(5);
d.print_state();
cout << "********** case 3: block size > 1" << endl;
cout << "***** remove right element" << endl;
d.remove(4);
d.print_state();
cout << "***** remove left element" << endl;
d.remove(0);
d.print_state();
}
//-
Dynamic_array::Dynamic_array() { //-
head_p = NULL; //-
size = 0; //-
} //-
//-
Dynamic_array::Dynamic_array(Dynamic_array & d) { //-
} //-
//-
Dynamic_array &Dynamic_array::operator=(Dynamic_array & d) { //-
return *this; //-
} //-
//-
Dynamic_array::~Dynamic_array() { //-
} //-
//-
void Dynamic_array::print_state(void) { //-
cout << "size:" << size << endl; //-
for (Block * p = head_p; p != NULL; p = p->next_p) { //-
cout << "\tsize:" << p->size << " elements:"; //-
for (int i = 0; i < p->size; i++) { //-
cout << p->a[i] << ' '; //-
} //-
cout << endl; //-
} //-
} //-
//-
int Dynamic_array::get_size(void) { //-
return size;
} //-
//-
int& Dynamic_array::operator[](int i) { //-
// check i for range error //-
if (i < 0 || i >= size) { //-
throw Subscript_range_exception(); //-
} //-
//-
// find target block and index //-
Block_position position = find_block(i); //-
//-
// return element at index i //-
return position.block_p->a[position.i]; //-
} //-
//-
void Dynamic_array::insert(int x, int i) { //-
// case 1: range error //-
if (i < 0 || i > size) { //-
throw Subscript_range_exception(); //-
} //-
//-
// case 2: empty array //-
if (size == 0) { //-
// create linked list consisting of a single new block //-
Block * new_block_p = new Block; //-
new_block_p->size = 1; //-
new_block_p->a[0] = x; //-
new_block_p->next_p = NULL; //-
//-
// insert new block //-
insert_blocks(NULL, new_block_p); //-
//-
// update total size //-
size++; //-
//-
return; //-
} //-
//-
// find target block and index //-
Block_position position = find_block(i); //-
//-
// case 3: non-empty array; new block not needed //-
if (position.block_p->size < BLOCK_SIZE) { //-
// shift block array right //-
for (int j = position.block_p->size; j > position.i; j--) { //-
position.block_p->a[j] = position.block_p->a[j-1]; //-
} //-
//-
// assign x //-
position.block_p->a[position.i] = x; //-
//-
// update array and block size //-
size++; //-
position.block_p->size++; //-
//-
// case 4: non-empty array; new block needed //-
} else { //-
// create new block //-
Block * new_block_p = new Block; //-
new_block_p->size = 1; //-
new_block_p->next_p = NULL; //-
//-
// case 4.a: insert x into old block //-
if (position.i < BLOCK_SIZE) { //-
// copy last array element to new block //-
new_block_p->a[0] = position.block_p->a[BLOCK_SIZE-1]; //-
//-
// shift old block array right //-
for (int j = position.block_p->size-1; j > position.i; j--) { //-
position.block_p->a[j] = position.block_p->a[j-1]; //-
} //-
//-
// assign x into old block //-
position.block_p->a[position.i] = x; //-
//-
// case 4.b: insert x into new block //-
} else { //-
new_block_p->a[0] = x; //-
} //-
//-
// update total size //-
size++; //-
//-
// insert new block into linked list //-
insert_blocks(position.block_p, new_block_p); //-
} //-
} //-
//-
void Dynamic_array::insert(Dynamic_array &p, int i) { //-
// case 1: range error //-
// case 2: parameter array empty //-
// case 3: array empty //-
// find target block and index //-
Block_position position = find_block(i); //-
// case 4: array non-empty; new blocks not needed //-
// case 5: array non-empty; new blocks needed //-
// copy p //-
Block * copy_p = copy_blocks(p.head_p); //-
// case 5.a: insert position at start of block //-
// case 5.b: insert position at middle of block //-
// case 5.c: insert position after end of block //-
// update total size //-
} //-
//-
void Dynamic_array::remove(int i) { //-
// case 1: range error //-
if (i < 0 || i >= get_size()) { //-
throw Subscript_range_exception(); //-
}
Block_position index = find_block(i);
cout << "Position : " << index.i << endl;
// find target block and index //-
// case 2: block size == 1 //-
if(index.block_p->size == 1) {
remove_blocks(NULL,index.block_p,index.block_p);
}
// case 3: block size > 1 //-
else if(index.block_p->size > 1) {
cout << "made it " << endl;
for (int j = index.i; j < BLOCK_SIZE-1; ++j){
index.block_p->a[j] = index.block_p->a[j + 1];
}
index.block_p->size--;
}
// update total size //-
size--;
} //-
//-
void Dynamic_array::remove(int start, int end) { //-
} //-
//-
// ********** private functions ********** //-
//-
// purpose //-
// return b where //-
// if i < size //-
// b.block_p->a[b.i] is the ith element overall //-
// else //-
// b.block_p->a[b.i-1] is the i-1st element overall //-
// //-
// if b.block_p == head_p //-
// b.pre_block_p is NULL //-
// else //-
// b.pre_block_p points to block preceding b.block_p //-
// preconditions //-
// i in [1..size] //-
Dynamic_array::Block_position Dynamic_array::find_block(int i) { //-
Block_position position; //-
//-
// scan Block list //-
position.i = i; //-
position.pre_block_p = NULL; //-
for (position.block_p = head_p; //-
position.block_p != NULL; //-
position.block_p = position.block_p->next_p) { //-
// found in current block //-
if (position.i < position.block_p->size) { //-
break; //-
} //-
//-
// special case: insert just after last element //-
if (i == size && position.block_p->next_p == NULL) { //-
break; //-
} //-
//-
// not found yet: advance //-
position.pre_block_p = position.block_p; //-
position.i -= position.block_p->size; //-
} //-
//-
return position; //-
} //-
//-
// purpose //-
// create a new linked list which is a copy of the list pointed to p //-
// return a pointer to the head of the new linked list //-
// preconditions //-
// p is the head of a possibly empty linked list of blocks //-
Dynamic_array::Block * Dynamic_array::copy_blocks(Block * p) { //-
Block * new_head_p = NULL; //-
Block * new_p; //-
while (p != NULL) { //-
// allocate and link in new block //-
if (new_head_p == NULL) { //-
new_p = new Block; //-
new_head_p = new_p; //-
} else { //-
new_p->next_p = new Block; //-
new_p = new_p->next_p; //-
} //-
//-
// copy the elements //-
new_p->size = p->size; //-
for (int i = 0; i < p->size; i++) { //-
new_p->a[i] = p->a[i]; //-
} //-
//-
// advance //-
p = p->next_p; //-
} //-
//-
// terminate new list //-
if (new_head_p != NULL) { //-
new_p->next_p = NULL; //-
} //-
//-
return new_head_p; //-
} //-
//-
// purpose //-
// insert the list headed by src_p into the list headed by head_p //-
// if dst_p is NULL //-
// insert the list at the start of the list headed by head_p //-
// else //-
// insert the list just after block dst_p //-
// preconditions //-
// list headed by src_p is non-empty //-
// list headed by src_p has no blocks in common with the list headed by head_p //-
void Dynamic_array::insert_blocks(Block * dst_p, Block * src_p) { //-
// find the last block in the list headed by src_p //-
Block * p = src_p; //-
while (p->next_p != NULL) { //-
p = p->next_p; //-
} //-
//-
// insert at head //-
if (dst_p == NULL) { // insert at head //-
p->next_p = head_p; //-
head_p = src_p; //-
//-
// insert after dst_p //-
} else { // insert after dst_p //-
p->next_p = dst_p->next_p; //-
dst_p->next_p = src_p; //-
} //-
} //-
//-
// purpose //-
// remove the blocks pointed to by start_p and end_p, and all the blocks between //-
// preconditions //-
// start_p and end_p point to blocks in the list headed by head_p //-
// end_p points to either the same block as start_p or a block to its right //-
// if start_p == head_p //-
// pre_start_p == NULL //-
// else //-
// pre_start_p points to the block immediately preceding start_p //-
// //-
void Dynamic_array::remove_blocks(Block * pre_start_p, Block * start_p, Block * end_p) { //-
// release the blocks //-
while (1) { //-
// release start_p //-
Block * p = start_p->next_p; //-
delete start_p; //-
//-
// advance //-
if (start_p == end_p) { //-
break; //-
} else { //-
start_p = p; //-
} //-
} //-
//-
// link left and right sublists //-
if (pre_start_p == NULL) { //-
head_p = end_p->next_p; //-
} else { //-
pre_start_p->next_p = start_p->next_p; //-
} //-
} //-
答案 0 :(得分：2)
int [BLOCK_SIZE];
只有5个元素从0..4索引。
因此d.insert（11,5）;和d.remove（5）;
会抛出异常。