View Compilation Error

0_0_21521222_20741.cpp: In function 'void add_edge(int, int, int)':
0_0_21521222_20741.cpp:21:7: error: 'tot' was not declared in this scope
     G[tot].from=from;
       ^
0_0_21521222_20741.cpp: In function 'void dfs(int, int)':
0_0_21521222_20741.cpp:31:9: error: 'i' was not declared in this scope
     for(i=head[x];i!=-1;i=G[i].next)
         ^
0_0_21521222_20741.cpp: In function 'int main()':
0_0_21521222_20741.cpp:47:9: error: 'tot' was not declared in this scope
         tot=0;
         ^