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Problem in Pointers!!

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Join Date: Oct 2009

Posts: 1

Reputation: its.avinash is an unknown quantity at this point

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its.avinash its.avinash is offline

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Problem in Pointers!!

Oct 24th, 2009

Hi all!
Please somebody explain me how this snippet is working!!

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
main()
{
float a 4.379;
char*p;
int i;
p=(char*)&a;
for(i=1;i<=3;i++)
printf("%02X",(unsigned char)p[i]);
}
main()
{
float a 4.379;
char*p;
int i;
p=(char*)&a;
for(i=1;i<=3;i++)
printf("%02X",(unsigned char)p[i]);
}

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Join Date: Jan 2008

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gerard4143 gerard4143 is offline

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Oct 24th, 2009

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Originally Posted by its.avinash

Hi all!
Please somebody explain me how this snippet is working!!
Help with Code Tags

C Syntax (Toggle Plain Text)
main()
{
float a 4.379;
char*p;
int i;
p=(char*)&a;
for(i=1;i<=3;i++)
printf("%02X",(unsigned char)p[i]);
}
main() { float a 4.379; char*p; int i; p=(char*)&a; for(i=1;i<=3;i++) printf("%02X",(unsigned char)p[i]); }

The code simply assigns the address of "a" to the character pointer "p" and then proceeds to check the value of the four bytes at address p[0], p[1],p[2], and p[3]...

Last edited by gerard4143; Oct 24th, 2009 at 8:20 pm.

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Join Date: May 2008

Posts: 33

Reputation: SVR is an unknown quantity at this point

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SVR

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Light Poster

Oct 24th, 2009

Well it looks like that's what it's supposed to do.
It should print the hex representation of the floating point number 4.379.

But I don't see how it will compile and it will only print 3 of the 4 hex bytes.

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Join Date: Sep 2009

Posts: 76

Reputation: Gaiety is an unknown quantity at this point

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Gaiety

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Junior Poster in Training

Oct 25th, 2009

function to display the floating number
the float numbers are stored in sign exponent mantissa fashion
furthur reading
http://steve.hollasch.net/cgindex/coding/ieeefloat.html

void test()
{
float f=5.25;
char *p=(char *)&f;
int i;
for(i = 3; i >= 0; i-- )
printf("%x\n",p[i]);
}
refer the attachment for out put on my system .

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Minds are like parachutes - they only work when they are open
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