View Compilation Error

0_0_25840494_1924.cpp: In function 'void dfs(int)':
0_0_25840494_1924.cpp:28:9: error: 'i' was not declared in this scope
     for(i=1;i<=adj[root][0];i++)  
         ^
0_0_25840494_1924.cpp: In function 'int main()':
0_0_25840494_1924.cpp:54:37: error: 'memset' was not declared in this scope
         memset(vis,false,sizeof(vis));  
                                     ^
0_0_25840494_1924.cpp:59:13: error: 'i' was not declared in this scope
         for(i=1;i<N;i++)//存图   
             ^