/in/foo.cc: In function 'bool heng()':
/in/foo.cc:12:26: error: 'memset' was not declared in this scope
   memset(t,true,sizeof(t));
                          ^
/in/foo.cc: In function 'bool shu()':
/in/foo.cc:25:27: error: 'memset' was not declared in this scope
   memset(t, true,sizeof(t));
                           ^
/in/foo.cc: In function 'bool quan()':
/in/foo.cc:44:28: error: 'memset' was not declared in this scope
    memset(t, true,sizeof(t));
                            ^