View Compilation Error

0_0_14811394_3596.cpp: In member function 'void river::input()':
0_0_14811394_3596.cpp:25:32: error: 'memset' was not declared in this scope
  memset(stone, 0, sizeof(stone));
                                ^
0_0_14811394_3596.cpp: In member function 'void river::dp()':
0_0_14811394_3596.cpp:38:40: error: 'memset' was not declared in this scope
  memset(minStone, 120, sizeof(minStone));
                                        ^
0_0_14811394_3596.cpp: At global scope:
0_0_14811394_3596.cpp:66:11: error: '::main' must return 'int'
 void main()
           ^