View Compilation Error

0_0_1864565_11618.cpp: In function `void pd(int, int, int, int)':
0_0_1864565_11618.cpp:30: error: `x' undeclared (first use this function)
0_0_1864565_11618.cpp:30: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1864565_11618.cpp:30: error: `y' undeclared (first use this function)