View Compilation Error

0_0_13799358_15577.cpp: In function 'int main()':
0_0_13799358_15577.cpp:34:43: error: 'memset' was not declared in this scope
         memset(m[t].rev,0,sizeof(m[t].rev));       
                                           ^
0_0_13799358_15577.cpp:43:45: error: 'memset' was not declared in this scope
         memset(f[t].wait,0,sizeof(f[t].wait));      
                                             ^
0_0_13799358_15577.cpp:103:29: error: 'memset' was not declared in this scope
     memset(out,0,sizeof(out));
                             ^