View Compilation Error

0_0_21152975_30210.cpp: In function 'int main()':
0_0_21152975_30210.cpp:25:19: error: unable to find numeric literal operator 'operator""i'
         for(int i=1i<=n;i++)
                   ^
0_0_21152975_30210.cpp:25:19: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes
0_0_21152975_30210.cpp:25:28: error: expected ';' before ')' token
         for(int i=1i<=n;i++)
                            ^
0_0_21152975_30210.cpp:34:38: error: 'w' was not declared in this scope
                 for(int j=20000;j>=k*w[i];j--)
                                      ^
0_0_21152975_30210.cpp:36:21: error: 'Dp' was not declared in this scope
                     Dp[j]=min(Dp[j],Dp[j-k*w[i]]+k);
                     ^