View Compilation Error

0_0_19418056_27327.cpp: In function 'int main()':
0_0_19418056_27327.cpp:214:20: error: 'a' was not declared in this scope
     scanf("%d %d",&a[i],&b[i]);
                    ^
0_0_19418056_27327.cpp:214:26: error: 'b' was not declared in this scope
     scanf("%d %d",&a[i],&b[i]);
                          ^
0_0_19418056_27327.cpp:238:15: error: 'len1' was not declared in this scope
    spfa(s,eh1,len1);
               ^
0_0_19418056_27327.cpp:239:15: error: 'len2' was not declared in this scope
    spfa(t,eh2,len2);
               ^