View Compilation Error

0_0_22113757_20831.cpp: In function 'long long int qpow(long long int, long long int)':
0_0_22113757_20831.cpp:9:21: error: 'n' was not declared in this scope
         ans=(ans*x)%n;
                     ^
0_0_22113757_20831.cpp: In function 'int main()':
0_0_22113757_20831.cpp:24:25: error: 'mod' was not declared in this scope
             if(qpow(2,x,mod)==1)
                         ^