下面我创建一个链接列表,然后尝试删除它,但是程序将编译并运行,但链接列表不会为我删除,程序卡在循环或其他东西(基本上它不会终止什么时候我应该手动杀死它?
任何人都可以建议我出错的地方,在写'deletePoly'函数之前一切都很好(即程序会编译并运行)没问题但是我已经经历了100次鳕鱼而且我不能似乎看到了问题所在。
这是我的代码:
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#define MEMORY_SIZE (15)
typedef struct link {
double coeff;
int pow;
struct link * next;
} poly;
poly *polyArray[MEMORY_SIZE];// array of 15 polynomials to play with
// /** The function prototypes */
void createPoly(poly **);
void showPoly(poly *);
void deletePoly(poly *);
int main(void) {
int a;
for( a = 0; a < MEMORY_SIZE; a++ )
{
polyArray[a] = NULL;//Initialise each element of the array of pointers to NULL
}//end for
createPoly(&polyArray[0]);
showPoly(polyArray[0]);
srand(time(NULL));
createPoly(&polyArray[1]);
showPoly(polyArray[1]);
showPoly(polyArray[0]);
int count;
for(count = 0; count < MEMORY_SIZE; count++)
{
deletePoly(polyArray[count]);
}
showPoly(polyArray[0]);
return 0;
}// End Main Function
//////////////////////////////////////////////////////////////////////////////////////
void createPoly(poly **node) {
poly *tempnode; //To hold the temporary last address
tempnode = (poly*)malloc( sizeof(poly) ); //create the first node
*node = tempnode; //Store the head address to the reference variable
int flag = 1 + rand()%3;; // A flag to control the number of terms
int counter;
for( counter = 0; counter <= flag; counter++ )
{
tempnode->pow = ( flag-counter );
tempnode->coeff = ( (double)(rand()%20) )/( (double)(1 + rand()%20) );
if( (counter < flag) && (counter >= 0) )
{
tempnode->next = (poly*)malloc( sizeof(poly) ); //Grow the list
}
else if ( counter == flag )
{
tempnode->next = NULL;
}
tempnode = tempnode->next;
}
}//end function createPoly
void deletePoly(poly *node) {
poly *temp;//Create pointer to poly called 'temp'
while( node->next != NULL );
{
temp = node->next;//Assign the address of the next node to 'temp'
free( node );//Delete the current node
node = temp;//Assign the address of the next node in the list to 'node'
}//end while
node = NULL;//Set pointer 'node' to NULL to prevent a "lingering" pointer
}//end function 'deletePoly'
void showPoly(poly * node) {
while(node->next != NULL) {
if(node->coeff == 0)
{
node = node->next;
}
else if(node->coeff == 1 && node->pow > 1)
{
printf("[x^%i]", node->pow);
node = node->next;
}
else if(node->coeff == 1 && node->pow == 1)
{
printf("[x]");
node = node->next;
}
else if(node->coeff != 0 && node->pow == 0)
{
printf("(%.2lf)", node->coeff);
node = node->next;
}
else if(node->pow == 0 && node->coeff == 0)
{
node = node->next;
}
else if(node->coeff != 1 && node->pow > 1 && node->coeff != 0)
{
printf("(%.2lf)[x^%i]", node->coeff, node->pow);
node = node->next;
}
else if(node->coeff != 1 && node->pow == 1 && node->coeff != 0)
{
printf("(%.2lf)[x]", node->coeff);// no need to print x to the power 0
node = node->next;
}
if(node->next != NULL)
{
printf(" + ");
}
}
}//end function showPoly
答案 0 :(得分:2)
删除代码应为:
void deletePoly(poly* node)
{
poly* next;
while (node != NULL)
{
next = node->next;
free(node);
node = next;
}
}