View Compilation Error

0_0_35999654_29733.cpp: In function 'void add(int, int, int, int&)':
0_0_35999654_29733.cpp:15:13: error: 'swap' was not declared in this scope
     swap(u,v);
             ^
0_0_35999654_29733.cpp: In function 'int rmq(int, int)':
0_0_35999654_29733.cpp:52:23: error: 'log2' was not declared in this scope
     int k=log2(y-x+1.0);
                       ^
0_0_35999654_29733.cpp: In function 'int LCA(int, int)':
0_0_35999654_29733.cpp:60:21: error: 'swap' was not declared in this scope
     if(x>y) swap(x,y);
                     ^
0_0_35999654_29733.cpp: In function 'int main()':
0_0_35999654_29733.cpp:68:18: error: 'scanf' was not declared in this scope
     scanf("%d",&c);
                  ^
0_0_35999654_29733.cpp:72:37: error: 'memset' was not declared in this scope
             memset(vis,0,sizeof(vis));
                                     ^
0_0_35999654_29733.cpp:89:59: error: 'printf' was not declared in this scope
                     printf("%d\n",dir[u]+dir[v]-2*dir[dis]);
                                                           ^