View Compilation Error

0_0_33696380_17929.cpp: In function 'int main()':
0_0_33696380_17929.cpp:69:46: error: 'struct Point' has no member named 'z'
             for (int j=i+1;j<=n;j++)if (a[i].z!=a[j].z)  seg[++cnt]=Seg{i,j,a[j]-a[i]};
                                              ^
0_0_33696380_17929.cpp:69:54: error: 'struct Point' has no member named 'z'
             for (int j=i+1;j<=n;j++)if (a[i].z!=a[j].z)  seg[++cnt]=Seg{i,j,a[j]-a[i]};
                                                      ^