View Compilation Error

0_0_30525606_21676.cpp: In function 'void init()':
0_0_30525606_21676.cpp:23:32: error: 'memset' was not declared in this scope
     memset(head,-1,sizeof(head));
                                ^
0_0_30525606_21676.cpp: In function 'int main()':
0_0_30525606_21676.cpp:138:14: error: 'i' was not declared in this scope
         for( i=0;i<n;i++){
              ^