View Compilation Error

0_0_15739297_12800.cpp: In function 'int main()':
0_0_15739297_12800.cpp:10:23: error: 'memset' was not declared in this scope
   memset(a,0,sizeof(a));
                       ^
0_0_15739297_12800.cpp:12:7: error: 'i' was not declared in this scope
   for(i=1;i<=n;i++)
       ^
0_0_15739297_12800.cpp:14:17: error: 'sort' was not declared in this scope
   sort(a+1,a+n+1);
                 ^
0_0_15739297_12800.cpp:15:7: error: 'i' was not declared in this scope
   for(i=1;i<=n;i++)
       ^
0_0_15739297_12800.cpp:17:7: error: 'i' was not declared in this scope
   for(i=1;i<=n;i++)
       ^
0_0_15739297_12800.cpp:22:21: error: 'i' was not declared in this scope
   printf("%d\n",sum[i-1]+1);
                     ^