View Compilation Error

0_0_25037443_29216.cpp: In function 'int main()':
0_0_25037443_29216.cpp:11:27: error: 'memset' was not declared in this scope
     memset(b,127,sizeof(b));
                           ^
0_0_25037443_29216.cpp:17:19: error: 'sort' was not declared in this scope
     sort(a+1,a+1+n);
                   ^