Help with Dynamic memory

I wanted to know if I want an dynamic array so which method is more suitable and why is it more suitable

method 1:

int *p,x;

p= new int;

cin>>x;//input the limit of array

for(int i=0; i<x; ++i)
cin>>p[i];

method 2:

int *p,x;

cin>>x;//input the limit of array

p= new int[x];

for(int i=0; i<x; ++i)
cin>>p[i];


and when we follow this method where does the value of input elemet store (my guess is buffer)

int *p,x;

cin>>x;//input the limit of array

for(int i=0; i<x; ++i)
cin>>p[i];

Any special reason you want to use an array here vice say a std::vector?

Quote:

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Originally Posted by Dr.Xperience

I wanted to know if I want an dynamic array so which method is more suitable and why is it more suitable

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Unless by chance x == 1, the first method is plain wrong. The second method is on the right track, except that x might not be positive, yet there was no error checking.

Furthermore, consider using a std::vector<int> instead of managing memory yourself.

hmm but if you use a primitive compiler like turbo C++ it doesn't give an error and ouput is also seems to be alright when x==1. And thank you all for your time and comments. I just wanted to manipulate memory manually so I asked for the help. hmm we have just learnt the basics in our university. one more thing confuse me how can we see the output of the program without using borland extentions like getch().

Quote:

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Originally Posted by Dr.Xperience

hmm but if you use a primitive compiler like turbo C++ it doesn't give an error and ouput is also seems to be alright when x==1.

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x == 1 is a case where the code should work. It is more interesting if x > 1, but even if the code "works", it is still wrong.

Quote:

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Originally Posted by Dr.Xperience

one more thing confuse me how can we see the output of the program without using borland extentions like getch().

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Run your program from a command prompt.

Quote:

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Originally Posted by laserlight

Run your program from a command prompt.

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Impressive never thought of that. I wonder how is ANSI C++ without borland extentions. If you may please reffer me any book or site from which I can learn core aspects of ANSIc++. I mean I can never image making a program without using clrscr(), gotoxy() etc. etc.
Thank You again for your comment.
I will be studying vector now.

Quote:

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Originally Posted by Dr.Xperience

If you may please reffer me any book or site from which I can learn core aspects of ANSIc++.

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I recommend Accelerated C++.

Thank You very much

You should not be studying ANSI C++. You should be studying ISO C++, since the latest standards of the language are managed by ISO, and not ANSI. The latest version being C++11, which is close to being finalized.

I came across the fact but still until they are in practise it will take some time to reach India more specifically our university.

Quote:

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Originally Posted by Dr.Xperience

I came across the fact but still until they are in practise it will take some time to reach India more specifically our university.

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If you adhere to what is taught here, you'll be stuck in the stone ages for ever.

Seriously, use a GOOD compiler, learn from MODERN books, and argue the point with *everyone* you meet.

Thanks for the advice . Infact to do so I have joint this forum to know new things. To learn more by myself.

Quote:

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Originally Posted by Dr.Xperience

Thanks for the advice . Infact to do so I have joint this forum to know new things. To learn more by myself.

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Now write some good programs, looking up the references whenever you're in doubt.

Yup thank you and by modern books which book you mean

Laser recommended a good one, and we have a list of book recommendations that you can browse through to find one that suits you best.

Okay Thank You