ç调整动态数组 [英] C resizing a dynamic array
问题描述
我创造了一个C类动态数组。我最有实现的一切,现在我测试出来。目前它得到一个调整大小时卡住。我用的printf的遵循问题。它看起来像大小调整工作,但是当我去加我的下一个项目后调整大小,它停止在那里。
我想这可能与我的内存分配,否则我指点和调整大小时释放阵列的方式做。我是新的C所以这些都是我的症结所在。
的#include<&ASSERT.H GT;
#包括LT&;&stdlib.h中GT;
#包括dynArray.h
#包括LT&;&stdio.h中GT;结构DynArr
{
TYPE *数据; / *指针数据阵列* /
INT大小; / *数组中元素的数量* /
INT能力; / *阵列的容量* /
};
/ * ************ ************************
动态数组功能
************************************************** ********************** * // *初始化(包括数据数组分配)动态数组。 参数:v指针动态数组
参数:动态数组的容量上限
pre:v不是空
岗位:内部数据数组可以容纳帽元素
岗位:V->数据不空
* /
无效initDynArr(DynArr * V,INT容量)
{
断言(容量大于0);
断言(ⅴ!= 0);
V->数据=(TYPE *)malloc的(的sizeof(TYPE)*容量);
断言(V->数据!= 0);
V->大小= 0;
V->容量=能力;
}/ *分配和初始化动态数组。 参数:盖所需的容量为达因阵列
pre:无
发帖:无
RET:一个非空指针的上限容量dynArr
并在它0的元素。
* /
DynArr * newDynArr(INT帽)
{
断言(帽大于0);
DynArr * R =(DynArr *)malloc的(的sizeof(DynArr));
断言(R = 0!);
initDynArr(R,帽);
返回ř;
}/ *动态数组解除分配数据数组。 参数:v指针动态数组
pre:无
岗位:d.data点为null
岗位:尺寸和容量为0
岗位:由V-&GT所使用的内存;数据被释放
* /
无效freeDynArr(DynArr * V)
{
如果(V->!数据= 0)
{
免费(V->数据); / *释放堆空间* /
V->数据= 0; / *使其指向空* /
}
V->大小= 0;
V->能力= 0;
}/ *解除分配数据阵列和动态数组URE。 参数:v指针动态数组
pre:无
岗位:由V-&GT所使用的内存;数据被释放
后:用d使用的内存被释放
* /
无效deleteDynArr(DynArr * V)
{
freeDynArr(五);
免费(V);
}/ *的大小调整底层数组是尺寸帽 参数:v指针动态数组
参数:盖新的期望容量
pre:v不是空
岗位:V有能力newCap
* /
无效_dynArrSetCapacity(DynArr * V,诠释newCap)
{
DynArr * newArr = newDynArr(newCap); //创建新帽新数组
INT X;
为(X = 0; X&下; sizeDynArr(五); X ++){
addDynArr(newArr,V->数据[X]); //复制数据
}
freeDynArr(五); //自由旧v
V->容量= newCap;
V->大小= newArr->大小;
V = newArr; //点v到新阵列
}/ *获取动态数组的大小 参数:v指针动态数组
pre:v不是空
发帖:无
RET:动态数组的大小
* /
INT sizeDynArr(DynArr * V)
{
返回V->大小;
}/ *添加一个元素的动态数组的末尾 参数:v指针动态数组
参数:val要添加到动态数组的末尾
pre:在dynArry不为空
岗位:1尺寸的增大
后:如果达产,产能翻倍
岗位:VAL是在数组中最后使用的位置
* /
无效addDynArr(DynArr * V,TYPE VAL)
{
/ *检查,看是否有大小调整是必要的* /
的printf(大小数:%d \\ TCAP数:%d \\ n,V>的大小,V>能力);
如果(V->大小> = V->能力){
的printf(在调整大小..);
_dynArrSetCapacity(V,2 * V->能力);
}
V->数据[V->大小= VAL; //调整大小后,这种情况不会发生。
V->大小++;
}/ *从指定位置获取从动态数组中的元素 参数:v指针动态数组
参数:POS整数索引来从元素
pre:v不是空
pre:v不是空
pre:POS<在DYN阵列和大于大小= 0
发帖:无更改DYN阵列
RET:值存储在索引POS
* /TYPE getDynArr(DynArr * V,INT POS)
{
/ *在指定位置返回数据元素阵列内* / 断言(正&下; sizeDynArr(ⅴ)及&放大器; POS&GT = 0); //值是零和大小之间
返回V->数据[POS]在位置//返回deferenced int值
}/ *在指定的位置从数组中删除元素,
变化等元素退一填补了国内空白 参数:v指针动态数组
参数:元素的IDX位置删除
pre:v不是空
pre:v不是空
pre:IDX<尺寸和IDX> = 0
岗位:在IDX的元素被删除
后:元素过去IDX移动退一万
* /
无效removeAtDynArr(DynArr * V,INT IDX)
{
INT I;
断言(IDX&下; sizeDynArr(ⅴ)及&放大器; idx的&GT = 0); 对于(i = IDX; I< sizeDynArr(五)-1;我++){
v [I]。数据= V [I + 1]。数据;
}
V-> size--;
}/ * ************ ************************
栈接口函数
************************************************** ********************** * // *返回布尔(带一个int codeD)证实是否将
动态数组叠层具有在其上的项目。 参数:v指针动态数组
pre:在dynArr不为空
发帖:无
RET:1如果为空,否则为0
* /
INT isEmptyDynArr(DynArr * V)
{
返回(sizeDynArr(ⅴ)== 0);
}/ *推的元件到堆栈的顶部 参数:v指针动态数组
参数:以法尔推入堆栈中的价值
pre:v不是空
岗位:1尺寸的增大
如果达产,产能翻倍
val为在堆栈的顶部
* /
无效pushDynArr(DynArr * V,TYPE VAL)
{
addDynArr(ⅴ,VAL);
}/ *返回元件在堆栈的顶部 参数:v指针动态数组
pre:v不是空
pre:v不是空
发帖:无更改堆栈
* /
TYPE topDynArr(DynArr * V)
{
返回getDynArr(ⅴ,sizeDynArr(ⅴ)-1);
}/ *删除堆栈顶部的元素 参数:v指针动态数组
pre:v不是空
pre:v不是空
岗位:大小减1
顶部已除去
* /
无效popDynArr(DynArr * V)
{
removeAtDynArr(ⅴ,sizeDynArr(ⅴ)-1);
}
INT主(INT ARGC,CHAR *的argv []){
DynArr * MYD = newDynArr(5);
INT X; addDynArr(MYD,1);
addDynArr(MYD,2);
//的printf(顶数:%d,sizeDynArr(MYD));
//输出(大小数:%d \\ Ttop的数:%d \\ n,sizeDynArr(MYD),topDynArr(MYD)); 为(X = 0; X&下; = 5; X ++){
addDynArr(MYD,X);
//输出(大小数:%d \\ Ttop的数:%d \\ n,sizeDynArr(MYD),topDynArr(MYD));
pushDynArr(MYD,X * 2);
//输出(大小数:%d \\ Ttop的数:%d \\ n,sizeDynArr(MYD),topDynArr(MYD));
}
的printf(HI); deleteDynArr(MYD); 返回0;
}
您函数 _dynArrSetCapacity
不工作打算,问题是出在下面几行:
V->容量= newCap;
V->大小= newArr->大小;
V = newArr; //点v到新阵列
}
最后的指令基本没用。 v
是一个指针。更改不会影响 _dynArrSetCapacity
之外的实际使用指针。因此, V->数据
是 0
在 addDynArr
和你会得到一个分段错误:
_dynArrSetCapacity(V,2 * V->能力);
}
V->数据[V->大小= VAL; //调整大小后,这种情况不会发生。
或者使用 V->数据= newArr-方式>数据
或指针使用指针代替
I'm creating a dynamic array data structure for a C class. I have most everything implemented and now I'm testing it out. It's currently getting stuck during a resize. I've used printf's to follow the issue. It looks like the resize is working, but when I go to add my next item post resize, it's stopping there.
I think it may have to do with my memory allocation or the way I'm pointing and freeing arrays during the resize. I'm new to C so these are my sticking points.
#include <assert.h>
#include <stdlib.h>
#include "dynArray.h"
#include <stdio.h>
struct DynArr
{
TYPE *data; /* pointer to the data array */
int size; /* Number of elements in the array */
int capacity; /* capacity of the array */
};
/* ************************************************************************
Dynamic Array Functions
************************************************************************ */
/* Initialize (including allocation of data array) dynamic array.
param: v pointer to the dynamic array
param: cap capacity of the dynamic array
pre: v is not null
post: internal data array can hold cap elements
post: v->data is not null
*/
void initDynArr(DynArr *v, int capacity)
{
assert(capacity > 0);
assert(v!= 0);
v->data = (TYPE *) malloc(sizeof(TYPE) * capacity);
assert(v->data != 0);
v->size = 0;
v->capacity = capacity;
}
/* Allocate and initialize dynamic array.
param: cap desired capacity for the dyn array
pre: none
post: none
ret: a non-null pointer to a dynArr of cap capacity
and 0 elements in it.
*/
DynArr* newDynArr(int cap)
{
assert(cap > 0);
DynArr *r = (DynArr *)malloc(sizeof( DynArr));
assert(r != 0);
initDynArr(r,cap);
return r;
}
/* Deallocate data array in dynamic array.
param: v pointer to the dynamic array
pre: none
post: d.data points to null
post: size and capacity are 0
post: the memory used by v->data is freed
*/
void freeDynArr(DynArr *v)
{
if(v->data != 0)
{
free(v->data); /* free the space on the heap */
v->data = 0; /* make it point to null */
}
v->size = 0;
v->capacity = 0;
}
/* Deallocate data array and the dynamic array ure.
param: v pointer to the dynamic array
pre: none
post: the memory used by v->data is freed
post: the memory used by d is freed
*/
void deleteDynArr(DynArr *v)
{
freeDynArr(v);
free(v);
}
/* Resizes the underlying array to be the size cap
param: v pointer to the dynamic array
param: cap the new desired capacity
pre: v is not null
post: v has capacity newCap
*/
void _dynArrSetCapacity(DynArr *v, int newCap)
{
DynArr* newArr = newDynArr(newCap); //Create new array with new cap
int x;
for(x = 0; x < sizeDynArr(v); x++){
addDynArr(newArr, v->data[x]); //copy data
}
freeDynArr(v); //free old v
v->capacity = newCap;
v->size = newArr->size;
v = newArr; //point v to new array
}
/* Get the size of the dynamic array
param: v pointer to the dynamic array
pre: v is not null
post: none
ret: the size of the dynamic array
*/
int sizeDynArr(DynArr *v)
{
return v->size;
}
/* Adds an element to the end of the dynamic array
param: v pointer to the dynamic array
param: val the value to add to the end of the dynamic array
pre: the dynArry is not null
post: size increases by 1
post: if reached capacity, capacity is doubled
post: val is in the last utilized position in the array
*/
void addDynArr(DynArr *v, TYPE val)
{
/* Check to see if a resize is necessary */
printf("size: %d\tcap: %d\n", v->size, v->capacity);
if(v->size >= v->capacity) {
printf("in resize..");
_dynArrSetCapacity(v, 2 * v->capacity);
}
v->data[v->size] = val; //after a resize this doesn't happen.
v->size++;
}
/* Get an element from the dynamic array from a specified position
param: v pointer to the dynamic array
param: pos integer index to get the element from
pre: v is not null
pre: v is not empty
pre: pos < size of the dyn array and >= 0
post: no changes to the dyn Array
ret: value stored at index pos
*/
TYPE getDynArr(DynArr *v, int pos)
{
/*returns data element at specified position within the array*/
assert(pos < sizeDynArr(v) && pos >= 0); //value is between zero and size
return v->data[pos]; //returns deferenced int value at position
}
/* Remove the element at the specified location from the array,
shifts other elements back one to fill the gap
param: v pointer to the dynamic array
param: idx location of element to remove
pre: v is not null
pre: v is not empty
pre: idx < size and idx >= 0
post: the element at idx is removed
post: the elements past idx are moved back one
*/
void removeAtDynArr(DynArr *v, int idx)
{
int i;
assert(idx < sizeDynArr(v) && idx >= 0);
for (i = idx; i < sizeDynArr(v)-1; i++){
v[i].data = v[i+1].data;
}
v->size--;
}
/* ************************************************************************
Stack Interface Functions
************************************************************************ */
/* Returns boolean (encoded in an int) demonstrating whether or not the
dynamic array stack has an item on it.
param: v pointer to the dynamic array
pre: the dynArr is not null
post: none
ret: 1 if empty, otherwise 0
*/
int isEmptyDynArr(DynArr *v)
{
return (sizeDynArr(v) == 0);
}
/* Push an element onto the top of the stack
param: v pointer to the dynamic array
param: val the value to push onto the stack
pre: v is not null
post: size increases by 1
if reached capacity, capacity is doubled
val is on the top of the stack
*/
void pushDynArr(DynArr *v, TYPE val)
{
addDynArr(v, val);
}
/* Returns the element at the top of the stack
param: v pointer to the dynamic array
pre: v is not null
pre: v is not empty
post: no changes to the stack
*/
TYPE topDynArr(DynArr *v)
{
return getDynArr(v, sizeDynArr(v)-1);
}
/* Removes the element on top of the stack
param: v pointer to the dynamic array
pre: v is not null
pre: v is not empty
post: size is decremented by 1
the top has been removed
*/
void popDynArr(DynArr *v)
{
removeAtDynArr(v, sizeDynArr(v)-1);
}
int main(int argc, char* argv[]){
DynArr* myD = newDynArr(5);
int x;
addDynArr(myD, 1);
addDynArr(myD, 2);
//printf("top: %d", sizeDynArr(myD));
//printf("size: %d\ttop: %d\n", sizeDynArr(myD), topDynArr(myD));
for(x = 0; x <= 5; x++){
addDynArr(myD, x);
//printf("size: %d\ttop: %d\n", sizeDynArr(myD), topDynArr(myD));
pushDynArr(myD, x * 2);
//printf("size: %d\ttop: %d\n", sizeDynArr(myD), topDynArr(myD));
}
printf("HI");
deleteDynArr(myD);
return 0;
}
Your function _dynArrSetCapacity
doesn't work as intended, the problem is in the following lines:
v->capacity = newCap;
v->size = newArr->size;
v = newArr; //point v to new array
}
The last instruction is basically useless. v
is a pointer. Changes won't affect the actual used pointer outside of _dynArrSetCapacity
. Thus v->data
is 0
in addDynArr
and you'll get a segmentation fault:
_dynArrSetCapacity(v, 2 * v->capacity);
}
v->data[v->size] = val; //after a resize this doesn't happen.
Either use v->data = newArr->data
or use a pointer on a pointer instead.
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