是数组越界了吗？怎么解决

Question

//定义结构体//
struct achievement
{
int number;
char name[20];
char sex;
int achievement1,achievement2,achievement3;
} tab_achievement[n];

void line3()
{
int j[10],i;
int k;
for(i=0; i<n; i++)
j[i]=0;

for(i=0; i<n; i++)
{
    k=tab_achievement[i].achievement3/10;
    j[k]++;
}
printf("answer\n");
for(i=0; i<10; i++)
    printf("%3d--%3d:%6d\n",i*10,(i+1)*10-1,j[i]);

}

Answer 1

for(i=0; i<n; i++)
{
k=tab_achievement[i].achievement3/10;
j[k]++;
}

j[k]有可能越界了，这个与你tab_achievement[i].achievement3的值有关