foo.cc: In function 'void MergeArray(int*, int*, int, int, int)':
foo.cc:4:14: error: 'NULL' was not declared in this scope
     if ( a== NULL || b== NULL  )
              ^~~~
foo.cc:6:9: error: 'cout' was not declared in this scope
         cout<<"输入数组为空，请检查"<<endl;
         ^~~~
foo.cc:6:49: error: 'endl' was not declared in this scope
         cout<<"输入数组为空，请检查"<<endl;
                                                 ^~~~
foo.cc:6:49: note: suggested alternative: 'enum'
         cout<<"输入数组为空，请检查"<<endl;
                                                 ^~~~
                                                 enum
foo.cc:12:9: error: 'cout' was not declared in this scope
         cout<<"输入数组长度错误，请检查"<<endl;
         ^~~~
foo.cc:12:55: error: 'endl' was not declared in this scope
         cout<<"输入数组长度错误，请检查"<<endl;
                                                       ^~~~
foo.cc:12:55: note: suggested alternative: 'enum'
         cout<<"输入数组长度错误，请检查"<<endl;
                                                       ^~~~
                                                       enum
foo.cc: In function 'void Test(char*, int*, int*, int, int, int)':
foo.cc:36:21: error: 'NULL' was not declared in this scope
     if (testName == NULL )
                     ^~~~
foo.cc:40:5: error: 'cout' was not declared in this scope
     cout<<testName<<" begins."<<endl;
     ^~~~
foo.cc:40:33: error: 'endl' was not declared in this scope
     cout<<testName<<" begins."<<endl;
                                 ^~~~
foo.cc:40:33: note: suggested alternative: 'enum'
     cout<<testName<<" begins."<<endl;
                                 ^~~~
                                 enum
foo.cc:42:5: error: 'DisplayArray' was not declared in this scope
     DisplayArray("A",arra1, len1);
     ^~~~~~~~~~~~

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