目标：使用插入排序从降序对指针数组进行排序。在对指针数组进行排序的同时，指针指向的数组也会对它进行排序。
void insert(int **table, int row)
{
// Local Declaration
int temp, current, walker;
// Statement
for(current = 1; current < row; current++)
{
temp = *table[current];
walker = current - 1;
while(walker >= 0 && temp > *table[walker])
{
*table[walker + 1] = *table[walker];
walker--;
}
*table[walker + 1] = temp;
}
return;
}
示例输出：
Before insertion sort:
1 -66
2 51 0
3 68 61 37
4 91 80 31 -9
5 59 42 -15 -19 -75
After insertion sort:
5 -66 -59 134218571 4132481 0
4 51 0 31 131357707
3 68 61 37
2 91 80
1 59
我应该创建每个数组的副本吗？当我使用插入排序交换数组时，还是有更有效的方法来完成任务？
完成计划：
/*********************************************************************************
** CIS 15BG Winter, 2013
***************
**
** Homework 3:
** Pointers, Dynamic Allocation of Memory, Ragged Arrays, and Sorting
**
**********************************************************************************
This program creates a dynamic table that can store a ragged 2D array
of integers, sorts each row then rearranges them by length
***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#ifdef _MSC_VER
#include <crtdbg.h> // needed to check for memory leaks (Windows only!)
#endif
#define MEM_ERROR printf("Not enough memory\n")
int** getRow(int *row);
void valiRow(int *row);
void getSize(int **table, int row);
int valiSize(int size);
void fillTable(int **table, int row);
void bubble(int **table, int row);
void insert(int **table, int row);
void save(int **table, int row);
int main (void)
{
// Local Declaration
int **table;
int row;
// Statement
table = getRow(&row);
getSize(table, row);
fillTable(table, row);
bubble(table, row);
insert(table, row);
#ifdef _MSC_VER
printf( _CrtDumpMemoryLeaks() ? "Memory Leak\n" : "No Memory Leak\n");
#endif
return 0;
}// main
/* getRow */
int** getRow(int *row)
{
// Local Declaration
int **table;
// Statement
printf("Please enter the number of rows (1-10): ");
scanf("%d", &*row);
valiRow(&*row);
table =(int**)calloc(*row+1, sizeof(int));
if(table == NULL)
MEM_ERROR, exit(100);
return table;
}
/* valiRow */
void valiRow(int *row)
{
// Statement
while(*row > 10 || *row < 1)
{
while(getchar() != '\n')
;
printf("Please enter a number between (1-10): ");
scanf("%d", &*row);
}
return;
}
/* getSize */
void getSize(int **table, int row)
{
// Local Declaration
int i, size;
// Statement
for(i = 0; i < row; i++)
{
printf("<ROW %2d> Please enter a size (1-15): ", i + 1);
scanf("%d", &size);
size = valiSize(size);
table[i] = (int*)calloc(size + 1, sizeof(int));
table[i][0] = size;
}
if(table == NULL)
MEM_ERROR, exit(101);
return;
}
/* valiSize */
int valiSize(int size)
{
// Statement
while(size > 15 || size < 1)
{
while(getchar() != '\n')
;
printf("Please enter a valid size (1-15): ");
scanf("%d", &size);
}
return size;
}
/* fillTable */
void fillTable(int **table, int row)
{
// Local Declaration
int random, i, j;
// Statement
srand(time(NULL));
for(i = 0; i < row; i++)
{
for(j = 0; j < (table[i][0]) + 1; j++)
{
random = -99 + rand() % 199;
table[i][j + 1] = random;
}
}
return;
}
/* bubble */
void bubble(int **table, int row)
{
// Local Declaration
int current, last, walker, temp;
int i, j;
// Statment
for(i = 0; i < row; i++)
{
last = table[i][0];
for(current = 1; current < last; current++)
{
for(walker = last; walker > current; walker--)
{
if(table[i][walker] > table[i][walker - 1])
{
temp = table[i][walker];
table[i][walker] = table[i][walker - 1];
table[i][walker - 1] = temp;
}
}
}
}
return;
}
/* insert */
void insert(int **table, int row)
{
// Local Declaration
int temp, current, walker;
// Statement
for(current = 1; current < row; current++)
{
temp = *table[current];
walker = current - 1;
while(walker >= 0 && temp > *table[walker])
{
*table[walker + 1] = *table[walker];
walker--;
}
*table[walker + 1] = temp;
}
return;
}
答案 0 :(得分：1)
您应该在插入函数中交换指针交换第一个元素（大小）的值并不意味着交换数组的其余元素。
void insert(int **table, int row)
{
// Local Declaration
int *temp, current, walker;
// Statement
for(current = 1; current < row; current++)
{
temp = table[current];
walker = current - 1;
while(walker >= 0 && *temp > *table[walker])
{
table[walker + 1] = table[walker];
walker--;
}
table[walker + 1] = temp;
}
return;
}
答案 1 :(得分：0)
memmove（）是你的朋友：
#include <stdio.h>
#include <string.h> /* for memmove() */
void insertion_sort(int **table, size_t cnt);
void insertion_sort(int **table, size_t cnt)
{
int *tmp;
size_t src,dst;
for(src = 1; src < cnt; src++)
{
tmp = table[src];
for(dst=src; dst-- > 0 && *tmp < *table[dst]; ) {;}
/* when we get out of the loop,
** table[dst] is the element BEFORE our insertion point,
** so re-increment it to point at the insertion point */
if (++dst == src) continue;
memmove(table+dst+1,table+dst, (src-dst) * sizeof table[0] );
table[dst] = tmp;
}
return 0;
}
int array[5] = { 11,12,13,14,15};
int *ptrs[5] = { array+3, array+0, array+4, array+2, array+1 };
int main (void)
{
size_t idx;
insertion_sort(ptrs, 5);
for (idx=0; idx < 5; idx++) {
printf ("[%zu] : %p: %d\n"
, idx, (void*) ptrs[idx], *ptrs[idx]
);
}
return 0;
}