View Compilation Error

0_0_18598652_15388.cpp: In function 'int main()':
0_0_18598652_15388.cpp:13:25: error: 'N' was not declared in this scope
     while (scanf("%d", &N) != EOF)
                         ^
0_0_18598652_15388.cpp:21:25: error: 'addedge' was not declared in this scope
             addedge(u, v); addedge(v, u);
                         ^
0_0_18598652_15388.cpp:24:14: error: 'dfs' was not declared in this scope
         dfs(1);
              ^