C程序 - 指针数组乘法

Question

该程序应该采用2个数组并对数组中的每个元素执行点乘积。

如果n的索引小于5，那么我的程序很好;然而，一旦数组的索引大于5，只有第一个数组中的第一个元素是错误的（我通过在函数中添加printf语句来检查）。我不知道如何解决这个错误。

#include <stdio.h> 

void multi_vec(int *v1, int *v2, int *v3, int n); 
int main(void) 
{ 
    int n, i; 
    int v1[n]; 
    int v2[n]; 
    int v3[n]; 
    printf("Enter the length of the two vectors\n"); 
    scanf("%d", &n); 
    printf("Enter numbers for the first array\n", n); 
    for (i = 0; i < n; i++) { 
     scanf("%d", &v1[i]); 
    } 
    printf("Enter numbers for the second array\n", n); 
    for (i = 0; i < n; i++) { 
     scanf("%d", &v2[i]); 
    } 

    multi_vec(v1, v2, v3, n); 

    for (i = 0; i < n; i++) { 
     printf("%d", v3[i]); 
    } 
    printf("\n"); 
    return 0; 
} 

void multi_vec(int *v1, int *v2, int *v3, int n) 
{ 
    int i; 
    for (i = 0; i < n; i++) { 
     *(v3+i) = *(v1+i) * *(v2+i); 
    } 
} 

Answer 1

正确的代码

#include <stdio.h> 

void multi_vec(int *v1, int *v2, int *v3, int n); 
int main(void) 
{ 
    int n, i; 
    printf("Enter the length of the two vectors\n"); 
    scanf("%d", &n); 
    int v1[n],v2[n],v3[n];  //you didn't initialize n 
    printf("Enter numbers for the first array\n"); //printf statements had extra ',n' 

    for (i = 0; i < n; i++) { 
     scanf("%d", &v1[i]); 
    } 
    printf("Enter numbers for the second array\n"); //printf statements had extra ',n' 
    for (i = 0; i < n; i++) { 
     scanf("%d", &v2[i]); 
    } 

    multi_vec(v1, v2, v3, n); 

    for (i = 0; i < n; i++) { 
     printf("%d ", v3[i]); 
    } 
    printf("\n"); 
    return 0; 
} 

void multi_vec(int *v1, int *v2, int *v3, int n) 
{ 
    int i; 
    for (i = 0; i < n; i++) { 
     *(v3+i) = *(v1+i) * *(v2+i); 
    } 
}