View Compilation Error

0_0_12968754_24664.cpp: In function `int main()':
0_0_12968754_24664.cpp:56: error: `f' undeclared (first use this function)
0_0_12968754_24664.cpp:56: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_12968754_24664.cpp:56: error: expected `;' before "if"
0_0_12968754_24664.cpp:60: error: expected primary-expression before "else"
0_0_12968754_24664.cpp:60: error: expected `;' before "else"
0_0_12968754_24664.cpp:64: error: expected primary-expression before "else"
0_0_12968754_24664.cpp:64: error: expected `;' before "else"