View Compilation Error

0_0_21485892_14195.cpp: In function 'void init()':
0_0_21485892_14195.cpp:11:29: error: 'memset' was not declared in this scope
     memset(bit,0,sizeof(bit));
                             ^
0_0_21485892_14195.cpp: In function 'void DP()':
0_0_21485892_14195.cpp:99:31: error: 'memset' was not declared in this scope
     memset(f[0],0,sizeof(f[0]));
                               ^
0_0_21485892_14195.cpp: In function 'int main()':
0_0_21485892_14195.cpp:136:39: error: 'memset' was not declared in this scope
         memset(num[N],0,sizeof(num[N]));
                                       ^