View Compilation Error

0_0_33348470_257.cpp:7:11: error: array bound is not an integer constant before ']' token
 } seg[MAXN]; 
           ^
0_0_33348470_257.cpp: In function 'int main()':
0_0_33348470_257.cpp:18:26: error: 'seg' was not declared in this scope
    scanf("%lf%lf%lf%lf",&seg[i].x1,&seg[i].y1,&seg[i].x2,&seg[i].y2); 
                          ^
0_0_33348470_257.cpp:20:16: error: 'seg' was not declared in this scope
    if(is_fxiji(seg[i],seg[j])) 
                ^