Main.cc: In function ‘void dfs(int)’: Main.cc:6:7: error: ‘i’ was not declared in this scope if(s[i][j]){ ^ Main.cc:9:7: error: ‘i’ was not declared in this scope if(f[i][j]=='X'){ ^ Main.cc: In function ‘int main()’: Main.cc:31:16: error: expected primary-expression before ‘]’ token s[0][j]=s[n+!][j]=-1; ^ Main.cc:37:12: error: too many arguments to function ‘void dfs(int)’ dfs(i,j); ^ Main.cc:5:6: note: declared here void dfs(int j){ ^~~