View Compilation Error

0_0_30437057_18039.cpp: In function 'void prime()':
0_0_30437057_18039.cpp:14:13: error: 'f' was not declared in this scope
         if(!f[i]){
             ^
0_0_30437057_18039.cpp:19:13: error: 'f' was not declared in this scope
             f[p[j]*i]=1;
             ^