printf whitespace control

Hi guys I need to now that I can control the white spaces in the printf("%5d") defined by 5.

In my program I need to control it to implement or decrement. So instead of using %5 what can I use.

I need ideas, thanks for help!

You can create the format string on the fly:

Code:

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char format[100];
sprintf(format, "%%%dd", 5); // or snprintf if available
printf(format, some_int);

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Quote:

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Originally Posted by man page

A field width or precision, or both, may be indicated by an asterisk `*'
or an asterisk followed by one or more decimal digits and a `$' instead
of a digit string. In this case, an int argument supplies the field
width or precision. A negative field width is treated as a left adjust-
ment flag followed by a positive field width; a negative precision is
treated as though it were missing. If a single format directive mixes
positional (nn$) and non-positional arguments, the results are undefined

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Eg.

Code:

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printf( "%*d\n", 5, some_int );

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Is this C or C++? This is C code, yet is posted in the C++ section.

actually I am trying to control

sprintf(*form, "%s", "%5d");

in this line %5d must be controlled by a variable!

and it is c++ but we're not using its GUI

Quote:

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in this line %5d must be controlled by a variable!

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What are you doing? You have already been given code to accomplish exactly this.

Quote:

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and it is c++ but we're not using its GUI

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What GUI? If you are using C++, then you can also do this the C++ way.

Code:

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std::cout << std::setw(5) << i << std::endl;

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sorry it is

sprintf(form, "%s", "%5d");

not *form

Quote:

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Originally Posted by komacan

and it is c++ but we're not using its GUI

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If you're using C++, why not use cout and iomanip's setw?

but this must be controlled by a variable "%5d" part must be controlled

and also I am obligated to write in C but in c++ file

So you should read the man page on printf/sprintf/etc, and note how to use a variable to control the precision.

I ve already read but nothing founr so I am here!

Then you need to read better.

Quote:

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Originally Posted by man 3 printf

A field width or precision, or both, may be indicated by an asterisk `*'
or an asterisk followed by one or more decimal digits and a `$' instead
of a digit string. In this case, an int argument supplies the field
width or precision. A negative field width is treated as a left adjust-
ment flag followed by a positive field width; a negative precision is
treated as though it were missing.

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