View Compilation Error

0_0_18059142_8453.cpp:20:15: error: 'edge' was not declared in this scope
     bool cmp2(edge a,edge b)  
               ^
0_0_18059142_8453.cpp:20:22: error: 'edge' was not declared in this scope
     bool cmp2(edge a,edge b)  
                      ^
0_0_18059142_8453.cpp:20:28: error: expression list treated as compound expression in initializer [-fpermissive]
     bool cmp2(edge a,edge b)  
                            ^
0_0_18059142_8453.cpp:21:5: error: expected ',' or ';' before '{' token
     {  
     ^