CODEWITHSUNDEEP
c++leading-zero
simryang
simryang

Reputation: 98

How to cout middle zero with leading zero via one cout statement in C++?

I need to display three values which is parsed from packet binary data(0x123400005678).

unsigned int k = 0x1234, l=0x0, m=0x5678;

I can display with four-digit hex value when I use cout three times.

#include <iostream>
#include <iomanip>
...
cout << "seperated cout" << endl;
cout << hex << setfill ('0') << setw (4) << k;
cout << hex << setfill ('0') << setw (4) << l;
cout << hex << setfill ('0') << setw (4) << m << endl;
....

seperated cout
123400005678

But when I use only one cout line, leading zero of '0x0' is omitted...

#include <iostream>
#include <iomanip>
...
cout << "oneline cout" << endl;
cout << hex << setfill ('0') << setw (4) << k << l << m << endl;
...

oneline cout
123405678

Is there anyway to display like '123400005678' with one line cout? Or is using cout three times only way to do this?

Thank you in advance.

Upvotes: 2

Views: 103

Answers (1)

Jerry Coffin
Jerry Coffin

Reputation: 490148

Field width isn't "sticky", so you need to set it again for each field you print out:

cout << hex << setfill ('0') << setw (4) << k << setw(4) << l << setw(4) << m << endl;

Result:

123400005678

The fill character is sticky though, so you usually want to set it back to a space character as soon as you're done using whatever other value you set:

cout << setfill(' ');

Upvotes: 3

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