View Compilation Error

0_0_28827537_9421.cpp: In function 'int main()':
0_0_28827537_9421.cpp:23:54: error: 'i' was not declared in this scope
    scanf("%d%d",&a[i].x,&a[i].y);            point[a[i].x+10][a[i].y+10]=1;        
                                                      ^