View Compilation Error

0_0_10040035_22019.cpp: In function `int main()':
0_0_10040035_22019.cpp:30: error: invalid conversion from `int (*)(arr*, arr*)' to `int (*)(const void*, const void*)'
0_0_10040035_22019.cpp:30: error:   initializing argument 4 of `void qsort(void*, size_t, size_t, int (*)(const void*, const void*))'