View Compilation Error

0_0_32020252_20072.cpp:5:11: error: '::main' must return 'int'
 void main(){
           ^
0_0_32020252_20072.cpp: In function 'int main()':
0_0_32020252_20072.cpp:36:33: error: 'memset' was not declared in this scope
         memset(str,a,sizeof(str));
                                 ^