View Compilation Error

0_0_26729263_2708.cpp: In function 'void powerval(int, int, int, int)':
0_0_26729263_2708.cpp:24:26: error: 'mod' was not declared in this scope
         sum1[id] = len % mod * val % mod;
                          ^
0_0_26729263_2708.cpp:30:37: error: 'mod' was not declared in this scope
         sum1[id] = sum1[id] * val % mod;
                                     ^
0_0_26729263_2708.cpp:36:44: error: 'mod' was not declared in this scope
         sum3[id] = (sum3[id] + val * val % mod * val % mod + 3*sum1[id] % mod * val % mod * (sum1[id] + val) % mod) % mod;
                                            ^