View Compilation Error

0_0_15421923_23103.cpp: In function 'bool judge(int, int, int, int)':
0_0_15421923_23103.cpp:24:49: error: lvalue required as left operand of assignment
     if(a[j].y-a[i].y != a[k].x-a[i].x && a[j].y = a[i].y)
                                                 ^