c - C 中不使用数组下标的内积函数

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我尝试编写一个内积函数，但程序无法正常工作。你能告诉我我的错误在哪里吗？

#include<stdio.h>
#include<stdlib.h>

int inner_product(const int *a, const int *b, int size) 
{
  int sum = 0, i;

  for (i=0; i<size; ++i) 
  sum += *(a+i) * *(b+i);

   return sum; 
}


int main()
{
    int n, a, b;
    printf("How many elements do you want to store?  ");
    scanf("%d",&n);

    printf("%d",inner_product(&a,&b,n));
    system("pause");
    return 0;
}

Answer 1

首先:

主要:

int n, a, b; //   a & b are not initialized
.
scanf("%d",&n); // Think what is the use of n here.
.
printf("%d",inner_product(&a,&b,n)); 
/*  You passed address of a and b, this is OK but the value they
 *  store is indeterminate as per the standard
 */

在函数中

 for (i=0; i<size; ++i) 
 sum += *(a+i) * *(b+i); // Accessing the memory out of bound for size>1 behavior is undefined
// Remember you have only two pointers which you can legally dereference ie a and b