View Compilation Error

0_0_20912236_28580.cpp: In function 'int main()':
0_0_20912236_28580.cpp:34:40: error: 'memset' was not declared in this scope
    memset(m[t].rev, 0, sizeof(m[t].rev));
                                        ^
0_0_20912236_28580.cpp:43:42: error: 'memset' was not declared in this scope
    memset(f[t].wait, 0, sizeof(f[t].wait));
                                          ^
0_0_20912236_28580.cpp:103:29: error: 'memset' was not declared in this scope
   memset(out, 0, sizeof(out));
                             ^