View Compilation Error

0_0_25963049_26205.cpp:5:1: error: expected ',' or ';' before 'const'
 const int mod = 1e9+7;
 ^
0_0_25963049_26205.cpp: In member function 'matrix matrix::operator*(matrix&)':
0_0_25963049_26205.cpp:18:20: error: 'mod' was not declared in this scope
     ans.a[i][j] %= mod;
                    ^
0_0_25963049_26205.cpp: In function 'int main()':
0_0_25963049_26205.cpp:66:88: error: 'mod' was not declared in this scope
    ans1 = (qmatrix.a[0][0]*ans[0] + qmatrix.a[0][1]*ans[1] + qmatrix.a[0][2]*ans[2]) % mod;
                                                                                        ^