View Compilation Error

0_0_8381808_18023.cpp: In function `int main()':
0_0_8381808_18023.cpp:117: error: `y0' undeclared (first use this function)
0_0_8381808_18023.cpp:117: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8381808_18023.cpp:123: error: request for member `size' in `dx', which is of non-class type `double[1000]'