View Compilation Error

0_0_6485282_18882.cpp: In function `int main()':
0_0_6485282_18882.cpp:19: error: invalid conversion from `void*' to `coordinates*'
0_0_6485282_18882.cpp:24: error: invalid conversion from `void*' to `coordinates*'
0_0_6485282_18882.cpp:42: error: invalid conversion from `void*' to `coordinates*'