View Compilation Error

0_0_37503027_15452.cpp: In function 'int change(int, int)':
0_0_37503027_15452.cpp:104:11: error: 'f1' was not declared in this scope
     while(f1!=f2)
           ^
0_0_37503027_15452.cpp:104:15: error: 'f2' was not declared in this scope
     while(f1!=f2)
               ^
0_0_37503027_15452.cpp: In function 'int main()':
0_0_37503027_15452.cpp:147:24: error: expected primary-expression before '=' token
             val[i]+=1; =
                        ^
0_0_37503027_15452.cpp:148:9: error: expected primary-expression before '}' token
         }
         ^