C语言 我正在丢失内存分配

Question

我需要使用malloc将最后的char *传递给另一个函数。Valgrind抱怨我没有初始化*temp，所以我使用了malloc。我遇到的问题是没有分配内存?我一直在摆弄这个，但不知道如何修复它。

我是否在for循环期间丢失了内存分配?

然后再用sprint for newCatID?

如有任何建议，不胜感激。

char *allocateCategoryID(ThisType *menu)
{
    char catID[ID_LEN]="";
    char *temp;
    char *newCatID;
    char *end;
    int idNum=0;
    int i=0;
    int j = 0;
    temp = malloc(ID_LEN-1);
    newCatID = malloc(ID_LEN*sizeof(char));
    /*get catID which strlen(catID)= ID_LEN*/

    for(i=1; i<ID_LEN; i++)/*FIRST VALGRIND ERROR IS HERE*/
    {
        temp[j]= catID[i];
        j++;
    }
    idNum = strtol(temp, &end, 10);/*NEXT VALGRIND ERROR IS HERE*/
    idNum++;
    sprintf(newCatID, "C%04i", idNum);/*NEXT VALGRIND ERROR IS HERE*/
    printf("New Category ID: %sn", newCatID);/*NEXT VALGRIND ERROR IS HERE*/
    free(temp);
    return newCatID;
}
Invalid write of size 1
0 bytes after a block of 4 alloc'd
Invalid read of size 1
0 bytes after a block of 5 alloc'd
Invalid write of size 1
0 bytes after a block of 5 alloc'd
Invalid read of size 1
0 bytes after a block of 5 alloc'd

Answer 1

在此循环的最后一次迭代中:

for(i=1; i<ID_LEN; i++)/*FIRST VALGRIND ERROR IS HERE*/
{
    temp[j]= catID[i];
    j++;
}

就越界了因为你为

中的LEN - 1分配了空间

temp = malloc(ID_LEN-1);

改变

temp = malloc(ID_LEN);
for(i = 1; i < ID_LEN; i++)
{
    temp[j] = catID[i];
    j++;
}
/* here you need to add the trailing '' */
temp[j] = '';