View Compilation Error

0_0_24442508_17213.cpp: In function 'void DFS1()':
0_0_24442508_17213.cpp:18:32: error: 'memset' was not declared in this scope
  memset(flag,false,sizeof(flag));
                                ^
0_0_24442508_17213.cpp: In function 'void DFS2()':
0_0_24442508_17213.cpp:63:32: error: 'memset' was not declared in this scope
  memset(flag,false,sizeof(flag));
                                ^
0_0_24442508_17213.cpp: At global scope:
0_0_24442508_17213.cpp:94:14: error: '::main' must return 'int'
 __int64 main()
              ^
0_0_24442508_17213.cpp: In function 'int main()':
0_0_24442508_17213.cpp:112:24: error: 'memset' was not declared in this scope
   memset(f,-1,sizeof(f));
                        ^