View Compilation Error

0_0_25411913_5035.cpp:4:11: error: '::main' must return 'int'
 void main(){
           ^
0_0_25411913_5035.cpp: In function 'int main()':
0_0_25411913_5035.cpp:10:25: error: 'memset' was not declared in this scope
   memset(a, 0, sizeof(a));
                         ^