View Compilation Error

0_0_11689334_2971.cpp: In function `long long int cal(int, int, int*)':
0_0_11689334_2971.cpp:68: error: `f' undeclared (first use this function)
0_0_11689334_2971.cpp:68: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11689334_2971.cpp:68: error: expected `;' at end of input
0_0_11689334_2971.cpp:68: error: expected `}' at end of input
0_0_11689334_2971.cpp:68: error: expected `}' at end of input
0_0_11689334_2971.cpp:68: error: expected `}' at end of input