View Compilation Error

0_0_34170005_27272.cpp: In function 'int main()':
0_0_34170005_27272.cpp:6:40: error: 'scanf' was not declared in this scope
     while(~scanf("%d%d%d%d",&n,&m,&k,&s)){
                                        ^
0_0_34170005_27272.cpp:7:30: error: 'memset' was not declared in this scope
         memset(dp,0,sizeof dp);
                              ^
0_0_34170005_27272.cpp:12:63: error: 'max' was not declared in this scope
                     dp[u][j]=max(dp[u][j],dp[u-1][j-q[i]]+w[i]);
                                                               ^
0_0_34170005_27272.cpp:13:33: error: 'puts' was not declared in this scope
         if(dp[s][m]<n) puts("-1");
                                 ^
0_0_34170005_27272.cpp:22:32: error: 'printf' was not declared in this scope
             printf("%d\n",m-ans);
                                ^