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Monday, November 6, 2017

C++ programming language part- 70 More abuot Integer Input and Output


More abuot  Integer Input and Output

In the program 47_3, write() function has used. Here, &p is the address of the variable. The (char*) is a type cast. The type cast is required because the first parameter to both read() and write() function is a character pointer. So the address of the object has to be type cast to a character pointer. The process is  int a; char b[5]; b=(char*) &a; the other is int=a,b; b=sizeof(a); 

Think about the following program

Program 47_9
            //inherit.demo
            #include
            #include
                        class customer             //class defined
            {
              char cname[21];
              int no_people;
              char ccat;
              float fcost;
              char cstart_date[9];

          public:
              void data_in()
               {
               cout<<"Type name \t";
               cin>>cname;
               cout<<" Type number of people \t";
               cin>>no_people;
               cout<<"Type catagory(N/S) \t";     // Normal or Special
               cin>>ccat;
               cout<<"Type the cost \t";
               cin>>fcost;
               cout<<"Type start date \t";
           cin>>cstart_date;
               }

              void data_out()
               {
               cout<<"name is= "<
               cout<<"No of people are = "<
   cout<<"catagory is = "<
               cout<<"cost is = "<
               cout<<"start date is = "<
               }
             };

             class custfile
               {
               customer c1;
               public:
               void data_in()
           {
               char creply;
               fstream fil("custfile.dat",ios::out); //ios::app
               do
               {
               c1.data_in();
               fil.write((char*)&c1,sizeof(c1));    //The (char*) is a type cast, The &c1 is address
               cout<<"wish to continue ";
               cin>>creply;
               }
              while (creply=='y');
              }

              void data_out()
          {
              char creply;
              fstream fil("custfile.dat",ios::in); //ios::app
              fil.read((char*)&c1,sizeof(c1));
              while (fil)
              {
              c1.data_out();
              fil.read((char*)&c1,sizeof(c1));
              }
          }
              };

              void main()
              {
               custfile cf1;
               cf1.data_in();
               cf1.data_out();

              }


Part- 86 assign the content of twostring


জ্ঞানকোষ প্রকাশনী
৩৮/২-ক, বাংলাবাজার (২য় তলা), ঢাকা।
       ফোনঃ ৭১১৮৪৪৩, ৮১১২৪৪১, ৮৬২৩২৫১.         
                                                     
কলকাতায় পরিবেশক/প্রাপ্তিস্থান
রিতা ইন্টারন্যাশনাল
৩৬, পি.এন. ব্যানার্জি রোড, কলকাতা
ফোনঃ ২৫১৩৮৩৫৯, ৯৮৩০৪৩৯৬৭৯, +৯১৯৮৩০৪৩৯৬৭৯