View Compilation Error

0_0_12170568_28277.cpp: In function `int main()':
0_0_12170568_28277.cpp:21: error: invalid conversion from `int (*)(const node*, const node*)' to `int (*)(const void*, const void*)'
0_0_12170568_28277.cpp:21: error:   initializing argument 4 of `void qsort(void*, size_t, size_t, int (*)(const void*, const void*))'