View Compilation Error

0_0_37780594_9076.cpp: In function 'void dfs(char)':
0_0_37780594_9076.cpp:17:18: error: 'strlen' was not declared in this scope
   l=strlen(str[i])-1;
                  ^
0_0_37780594_9076.cpp:19:10: error: expected primary-expression before ')' token
    if(n==) {   //搜索到m终点返回
          ^
0_0_37780594_9076.cpp: In function 'int main()':
0_0_37780594_9076.cpp:40:27: error: 'memset' was not declared in this scope
   memset(vis,0,sizeof(vis));
                           ^