View Compilation Error

0_0_17057871_14249.cpp: In function 'int main()':
0_0_17057871_14249.cpp:59:25: error: 'f1' was not declared in this scope
                         f1=1;
                         ^
0_0_17057871_14249.cpp:68:29: error: 'f1' was not declared in this scope
                             f1=1;
                             ^
0_0_17057871_14249.cpp:80:25: error: 'f1' was not declared in this scope
                         f1=1;
                         ^