我意识到尝试访问无法访问的内存会导致分段错误。我似乎无法找到问题，为什么会发生这种情况。任何帮助都是极好的！它发生在如下：
Enter the number of elements: 3
Enter the next number: 11
Enter the next number: 22
Enter the next number: 33
How would like to sum the elements?
(1) iteratively
(2) recursively
1
Segmentation fault (core dumped)
以下是我的代码：
main.c中
#include <stdio.h>
#include <stdlib.h>
#include "stackDefs.h"
int main()
{
int intArray[MAX_ARR_SIZE];
int numElm = 0;
int result = 0;
int choice, rc;
rc = getArrayData(intArray, &numElm);
if (rc < 0)
exit(1);
printf("\nHow would like to sum the elements?\n");
printf(" (1) iteratively\n");
printf(" (2) recursively\n");
scanf("%d", &choice);
StackType *stk;
st_init(stk);
switch (choice) {
case 1:
sumIterative(stk, numElm, intArray, &result);
printf("Sum is %d\n", result);
break;
case 2:
sumRecursive(stk, numElm, intArray, &result);
printf("Sum is %d\n", result);
}
return 0;
}
int getArrayData(int *arr, int *num)
{
int currCount = 0;
printf("\nEnter the number of elements: ");
scanf("%d", num);
if (*num >= MAX_ARR_SIZE) {
printf("Too many elements\n");
return C_NOK;
}
while (currCount < *num) {
printf("Enter the next number: ");
scanf("%d", arr+currCount);
++currCount;
}
return C_OK;
}
stack.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "stackDefs.h"
void st_init(StackType *stk){
stk->numFrames = 0;
stk = calloc(stk->numFrames, sizeof(StackType));
}
void st_dump(StackType *stk)
{
int i, j, k;
printf(" -- STACK --\n");
for (i=0; i<stk->numFrames; ++i) {
printf(" ---- FRAME #%d: %s \n", i,
stk->frames[i].funcName);
for (j=0; j<stk->frames[i].numParams; j++) {
printf(" ------ param %d: %4d \n", j, stk->frames[i].params[j]);
}
}
printf(" -- END OF STACK --\n\n");
}
void st_push(StackType *stk, char *fname, int numP, ParamType **paramArr){
strcpy(stk->frames[stk->numFrames].funcName, fname);
stk->frames[stk->numFrames].numParams = numP;
int i = 0;
for(i = 0; i < numP; i++){
stk->frames[stk->numFrames].params[i] = (ParamType *) paramArr[i];
}
stk->numFrames++;
st_dump(stk);
}
void st_pop(StackType *stk){
st_dump(stk);
stk->numFrames--;
free(stk->frames->params);
}
void st_createParam(char *name, int *valuePtr, ParamType **newParam) {
printf("made it 1!");
ParamType *temp;
temp = (ParamType*) malloc(sizeof(ParamType));
strcpy(temp->name, name);
temp->value = valuePtr;
*newParam = temp;
printf("made it 2!");
}
loop.c中
#include <stdio.h>
#include <string.h>
#include "stackDefs.h"
void sumIterative(StackType* stk, int numElements, int *intArray, int *sum){
ParamType **temp0;
ParamType **temp1;
ParamType **temp[2];
st_createParam("numElements", &numElements, temp0);
st_createParam("sum", sum, temp1);
temp[0] = temp0;
temp[1] = temp1;
st_push(stk, "sumIterative", 2, *temp);
int i;
*sum = 0;
for (i=0; i<numElements; ++i)
*sum += intArray[i];
st_pop(stk);
}
void sumRecursive(StackType* stk, int numElements, int *intArray, int *sum){
ParamType **temp0;
ParamType **temp1;
ParamType *temp[2];
st_createParam("numElements", &numElements, temp0);
st_createParam("sum", sum, temp1);
temp[0] = *temp0;
temp[1] = *temp1;
st_push(stk, "sumRecursive", 2, temp);
if (numElements == 0) {
*sum = 0;
st_pop(stk);
return;
}
sumRecursive(stk, numElements-1, intArray, sum);
*sum += intArray[numElements-1];
st_pop(stk);
}
stackDefs.h
#define MAX_FRAMES 32
#define MAX_PARAMS 8
#define MAX_ARR_SIZE 16
#define MAX_STR 32
#define C_OK 0
#define C_NOK -1
typedef struct {
char name[MAX_STR];
int *value;
} ParamType;
typedef struct {
char funcName[MAX_STR];
int numParams;
ParamType *params[MAX_PARAMS];
} FrameType;
typedef struct {
int numFrames;
FrameType frames[MAX_FRAMES];
} StackType;
/* Stack functions */
void st_init(StackType*);
void st_push(StackType*, char*, int, ParamType**);
void st_pop(StackType*);
void st_dump(StackType*);
void st_createParam(char*, int*, ParamType**);
/* Loop functions */
void sumIterative(StackType*, int, int*, int*);
void sumRecursive(StackType*, int, int*, int*);
int getArrayData(int*, int*);
使用Valgrind我得到了这个：
==3681== Use of uninitialised value of size 4
==3681== at 0x8048A57: st_createParam (in /home/admin/Desktop/a3/a3)
==3681== by 0x8048718: sumIterative (in /home/admin/Desktop/a3/a3)
==3681== by 0x8048618: main (in /home/admin/Desktop/a3/a3)
==3681==
==3681==
==3681== Process terminating with default action of signal 11 (SIGSEGV)
==3681== Bad permissions for mapped region at address 0x40A2F49
==3681== at 0x8048A57: st_createParam (in /home/admin/Desktop/a3/a3)
==3681== by 0x8048718: sumIterative (in /home/admin/Desktop/a3/a3)
==3681== by 0x8048618: main (in /home/admin/Desktop/a3/a3)
==3681==
==3681== HEAP SUMMARY:
==3681== in use at exit: 2,216 bytes in 2 blocks
==3681== total heap usage: 2 allocs, 0 frees, 2,216 bytes allocated
==3681==
==3681== LEAK SUMMARY:
==3681== definitely lost: 2,180 bytes in 1 blocks
==3681== indirectly lost: 0 bytes in 0 blocks
==3681== possibly lost: 0 bytes in 0 blocks
==3681== still reachable: 36 bytes in 1 blocks
==3681== suppressed: 0 bytes in 0 blocks
==3681== Rerun with --leak-check=full to see details of leaked memory
==3681==
==3681== For counts of detected and suppressed errors, rerun with: -v
==3681== Use --track-origins=yes to see where uninitialised values come from
==3681== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
Segmentation fault (core dumped)
答案 0 :(得分：0)
在将st_init传递给main之前，您需要为StackType stk_obj;
StackType *stk = &stk_obj;
st_init(stk);
分配存储空间。最简单的方法可能只是在&中声明它：
main或者你可以省去指针，但是如果你采用这种方法，你需要在for (f = 0; f < forum.length; f++) {
end = columnArray.length - 1;
object = forum[f];
for (property in object)
{
value = object[property];
if (property === columnArray[end]) {
tableRowData = "<td>" + value + "</td></tr>";
} else {
tableRowData = "<td>" + value + "</td>";
}
tableRowData2 += tableRowData;
tableRowData = "";
}
finalTableData = "<tr>" + tableRowData2;
finalTableData2 += finalTableData;
tableRowData2 = "";
}
的任何地方添加for (i = 0; i < forum.length; i++) {}
。