我试图用C语言编写一个有一个函数分割数组的程序。它接受一个指向动态分配数组的指针，然后将其分成两半，即左半和右半。
程序示例的代码为：
#include<stdio.h>
#include<stdlib.h>
void split_array(int *A, int x)
{
int *left=NULL, *right=NULL, i, mid=0;
mid=x/2;
left=(int*)malloc(sizeof(int)*mid);
if(left==NULL)
{
printf("\nError allocating memory. Aborting!\n\n");
exit(1);
}
if(x%2==0)
{
right=(int*)malloc(sizeof(int)*mid);
if(right==NULL)
{
printf("\nError allocating memory. Aborting!\n\n");
exit(1);
}
}
else
{
right=(int*)malloc(sizeof(int)*(mid+1));
if(right==NULL)
{
printf("\nError allocating memory. Aborting!\n\n");
exit(1);
}
}
for(i=0;i<mid;i++)
left[i]=A[i];
for(i=mid;i<x;i++)
right[i]=A[i];
printf("\nleft: ");
for(i=0;i<mid;i++)
printf("%d ", left[i]);
printf("\n");
printf("\nright: ");
for(i=mid;i<x;i++)
printf("%d ", right[i]);
printf("\n");
free(left);
free(right);
left=NULL;
right=NULL;
}
int main()
{
int *arr=NULL, i, l=0;
printf("Enter number of elements required in array: ");
scanf("%d", &l);
arr=(int*)malloc(sizeof(int)*l);
if(arr==NULL)
{
printf("\nError allocating memory. Aborting!\n\n");
exit(1);
}
printf("Enter the elements: ");
for(i=0;i<l;i++)
scanf("%d", &arr[i]);
printf("\nYou entered the elements: ");
for(i=0;i<l;i++)
printf("%d ", arr[i]);
printf("\n");
split_array(arr, l);
free(arr);
arr=NULL;
return 0;
}
只要数组的长度小于或等于6，它就会正常执行。但当长度大于或等于7时，它将开始抛出错误消息。
输出示例如下：
Enter number of elements required in array: 7 Enter the elements: 1 2 3 4 5 6 7
You entered the elements: 1 2 3 4 5 6 7
left: 1 2 3
right: 4 5 6 7
*** glibc detected *** ./a.out: free(): invalid next size (fast): 0x0000000002451060 ***
======= Backtrace: ========= /lib/x86_64-linux-gnu/libc.so.6(+0x76a16)[0x7f1d2d616a16] /lib/x86left: 1 2 3
right: 4 5 6 7
*** glibc detected *** ./a.out: free(): invalid next size (fast): 0x00000_64-linux-gnu/libc.so.6(cfree+0x6c)[0x7f1d2d61b7bc] ./a.out[0x400910] ./a.out[0x400a3e] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd)[0x7f1d2d5beead] ./a.out[0x400619]
======= Memory map: ======== 00400000-00401000 r-xp 00000000 08:01 25954902 /home/ralph/Desktop/a.out 00600000-00601000 rw-p 00000000 08:01 25954902 /home/ralph/Desktop/a.out 02451000-02472000 rw-p 00000000 00:00 0 [heap] 7f1d28000000-7f1d28021000 rw-p 00000000 00:00 0 7f1d28021000-7f1d2c000000 ---p 00000000 00:00 0 7f1d2d38a000-7f1d2d39f000 r-xp 00000000 08:01 17957772 /lib/x86_64-linux-gnu/libgcc_s.so.1 7f1d2d39f000-7f1d2d59f000 ---p 00015000 08:01 17957772 /lib/x86_64-linux-gnu/libgcc_s.so.1 7f1d2d59f000-7f1d2d5a0000 rw-p 00015000 08:01 17957772 /lib/x86_64-linux-gnu/libgcc_s.so.1 7f1d2d5a0000-7f1d2d722000 r-xp 00000000 08:01 17956950 /lib/x86_64-linux-gnu/libc-2.13.so 7f1d2d722000-7f1d2d922000 ---p 00182000 08:01 17956950 /lib/x86_64-linux-gnu/libc-2.13.so 7f1d2d922000-7f1d2d926000 r--p 00182000 08:01 17956950 /lib/x86_64-linux-gnu/libc-2.13.so 7f1d2d926000-7f1d2d927000 rw-p 00186000 08:01 17956950 /lib/x86_64-linux-gnu/libc-2.13.so 7f1d2d927000-7f1d2d92c000 rw-p 00000000 00:00 0 7f1d2d92c000-7f1d2d94c000 r-xp 00000000 08:01 17957749 /lib/x86_64-linux-gnu/ld-2.13.so 7f1d2db2c000-7f1d2db2f000 rw-p 00000000 00:00 0 7f1d2db47000-7f1d2db4b000 rw-p 00000000 00:00 0 7f1d2db4b000-7f1d2db4c000 r--p 0001f000 08:01 17957749 /lib/x86_64-linux-gnu/ld-2.13.so 7f1d2db4c000-7f1d2db4d000 rw-p 00020000 08:01 17957749 /lib/x86_64-linux-gnu/ld-2.13.so 7f1d2db4d000-7f1d2db4e000 rw-p 00000000 00:00 0 7fff59345000-7fff59366000 rw-p 00000000 00:00 0 [stack]
7fff593ff000-7fff59400000 r-xp 00000000 00:00 0 [vdso] ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall] Aborted
我使用gnu/linux amd64和gcc 4.7.2。关于为什么会发生这种事有什么解释吗？
谢谢
最佳答案
这些线
for(i=mid;i<x;i++)
right[i]=A[i];
还有这些台词
for(i=mid;i<x;i++)
printf("%d ", right[i]);
都错了。您访问的
right超出界限，并导致未定义的行为。他们需要：
for(i=mid;i<x;i++)
right[i-mid]=A[i];
和
for(i=mid;i<x;i++)
printf("%d ", right[i-mid]);
关于c - 在C中使用free()时出错，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/28358666/