View Compilation Error

0_0_36490390_21051.cpp: In member function 'void Matrix::init(int)':
0_0_36490390_21051.cpp:9:33: error: 'memset' was not declared in this scope
             memset(a,0,sizeof(a));
                                 ^
0_0_36490390_21051.cpp: In member function 'Matrix Matrix::operator*(Matrix)':
0_0_36490390_21051.cpp:36:36: error: 'memset' was not declared in this scope
             memset(p.a,0,sizeof p.a);
                                    ^
0_0_36490390_21051.cpp: In member function 'Matrix Matrix::power_1(int)':
0_0_36490390_21051.cpp:45:40: error: 'memset' was not declared in this scope
             memset(ans.a,0,sizeof ans.a);
                                        ^