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Where did you find that obscure sqrt() function? I guess it was originally using float rather than double .
Remove that and use the C standard library sqrt() function by including math.h.
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actually i changed it to double n include math.h also but output seem same as before.
source for square function
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You must remove your version of the sqrt() function. Otherwise it will be used instead of the standard library version.
Your version uses ugly programming that directly accesses a single precision (float ) value. By changing the type to double it won't work any more.
[EDIT]: Forget that. It is an approximation that might be from http://www.azillionmonkeys.com/qed/sqroot.html[^].
But such hardware dependant code should not be used.
modified 29-Jul-14 6:41am.
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Quote: double sqrt (double f)
{
double x, z, tempf;
unsigned long *tfptr = ((unsigned long *)&tempf) + 1;
tempf = f;
*tfptr = (0xbfcdd90a - *tfptr)>>1;
x = tempf;
z = f*0.5;
x = (1.5*x) - (x*x)*(x*z); //The more you make replicates of this statement
//the higher the accuracy, here only 2 replicates are used
x = (1.5*x) - (x*x)*(x*z);
return x*f;
}
That is really messy!
You are using uninitialized variables (that is garbage).
It looks you want to implement the Babylonian method[^] but you do nothing for computing the initial guess.
The following code is based on that very Wikipedia page.
void initial_guess(double r, int *pa, int *pn)
{
*pn = 0;
while ( r < 1.0)
{
r *= 100.0;
--(*pn);
}
while ( r >= 100.0 )
{
r /= 100.0;
++(*pn);
}
*pa = (r < 10.0) ? 2 : 6;
}
double square_root(double r)
{
int a, i, n;
initial_guess(r, &a, &n);
double x=1.0;
while (n < 0)
{
x/=10.0;
++n;
}
while(n > 0)
{
x *= 10.0;
--n;
}
x *= a;
for (i = 0; i<10; ++i) {
x = 0.5 * (x + r/x);
}
return x;
}
THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?!
-- C++ FQA Lite
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You are welcome.
THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?!
-- C++ FQA Lite
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using
for(i=0;i<5;i++)
{
float f= ((float)rand()/(float)(RAND_MAX))*a;
y=square(f);
sum +=y;
}
printf("\n summation of squared number is:=%f\t",sum);
gives output but not the exact answer..
any solution actually i want to find the summation of that squared float number..
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How do you check the result?
THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?!
-- C++ FQA Lite
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Quote:
Generated random number || Squaring of random number:
=========================================================
0.035679 ----- 0.001273
0.079935 ----- 0.006390
0.033320 ----- 0.001110
0.042424 ----- 0.001800
0.012387 ----- 0.000153
summation of squared number is:=0.010346
where the actual summation should be 0.10726
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You are wrong, the output of the following program:
int main()
{
int i;
double sum = 0.0;
double a[] =
{
0.035679,
0.079935,
0.03332,
0.042424,
0.012387
};
for (i=0; i<sizeof(a)/sizeof(a[0]); ++i)
{
double sq = square_root(a[i]);
printf("a[%d] = %g, sqrt(a[%d])=%g\n", i, a[i], i, sq);
sum += sq;
}
printf("sum of square roots = %g\n", sum);
}
is
a[0] = 0.035679, sqrt(a[0])=0.188889
a[1] = 0.079935, sqrt(a[1])=0.282728
a[2] = 0.03332, sqrt(a[2])=0.182538
a[3] = 0.042424, sqrt(a[3])=0.205971
a[4] = 0.012387, sqrt(a[4])=0.111297
sum of square roots = 0.971422
That is correct (at least according to Excel ).
THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?!
-- C++ FQA Lite
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this is different program its squaring of number not square root...
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How do you compute the squares?
This program:
#include <stdio.h>
int main()
{
double a [] =
{
0.035679,
0.079935,
0.033320,
0.042424,
0.012387
};
double sum, square;
int n;
sum = 0.0;
for (n=0; n<sizeof(a)/sizeof(a[0]); ++n)
{
square = a[n]*a[n];
sum += square;
printf("%g ----> %g\n", a[n], square);
}
printf("sum of squares: %g\n", sum);
return 0;
}
gives:
0.035679 ----> 0.00127299
0.079935 ----> 0.0063896
0.03332 ----> 0.00111022
0.042424 ----> 0.0017998
0.012387 ----> 0.000153438
sum of squares: 0.0107261
THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?!
-- C++ FQA Lite
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Are you needing the sqaure or the square root?
PS and the sum of your numbers is 0.010726.
"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
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Actually i need square but its solve i got it but i am not able to get the summation value of the square number correctly .plz help me out..
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While migrating VC++ code from VS6 (1998) to VS5(later year) I had to remove __STDC__ from project properties-Predecessors. It fix lot of 'tagVariant' related errors.
if i have __STDC__ in project properties - preprpcessors
I get this
xyz.cpp
c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\atlcomcli.h(443) : error C2039: 'vt' : is not a member of 'tagVARIANT'
c:\program files (x86)\microsoft visual studio 8\vc\platformsdk\include\oaidl.h(424) : see declaration of 'tagVARIANT'
c:\program files (x86)\microsoft visual studio 8\vc\atlmfc\include\atlcomcli.h(443) : error C2039: 'vt' : is not a member of 'tagVARIANT'
Next what happened is function definitions were not recognized in many of the project file. so I added #define
__STDC__ in problem files which also took care of many unrecognized function definition related errors.
Now the project is left with only one error in compiling one file which says "Fetal error (1017) invalid integer constant expression in ctype.h" and the code its pointing to line number 362 in ctype.h #define !__STDC__ etc Any ideas - suggestions ? Pls help
I tried to - Remove any #define __STDC__ that I added locally. Also remove __STDC__ from Preprocessor definitions if you haven't done so already. Selected all the .c files in the solution explorer and select properties in the solution explorer context menu. In the properties dialog select /Za for C/C++\Language\Disable Language Extensions property.
Which took me back to -> error C2065: ‘xyz’: undeclared identifier : error C2182: ‘pqr’ : illegal use of type 'void' : error C2065: ‘some variable’ : undeclared identifier : error C2146: syntax error : missing ';' before identifier ‘classname’ : error C2143: syntax error : missing ';' before '*' : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int : error C2040: ‘variable2’ : 'int *' differs in levels of indirection from ''unknown-type'' . . .
Reference : http://social.msdn.microsoft.com/Forums/en-US/e68b0af5-ed25-4953-80e7-e88463149b77/fatal-error-1017-invalid-integer-constant-expression-in-ctypeh-during-migration-from-vs6-to-vs5?forum=vcgeneral
modified 28-Jul-14 9:44am.
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__STDC__ is defined by the Microsoft compiler when compiling C files with the /Za option. It is never defined when compiling C++ files. You should not define it somewhere in your code or as project global definition, or edit any system header files.
If you have a mixed setup of C and C++ files, you can try to rename the C files to *.cpp to force compilation as C++.
Finally you have to fix all errors in your source code by inspecting them and take the appropiate actions.
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I get that - __STDC__ should be there only with .C files.
my application also uses cygwin. I think this C files files were there because of cygwin.
forcing .C files as .CPP will it not cause any problem when application makes use of cygwin ?
Is it okey if in the .C file property i give an option 'Compile as C++ file' ?
Well just an update - It did not work. It gave me tons of syntax errors in my .c/.cpp files.
modified 28-Jul-14 10:59am.
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In most cases there is no problem when compiling C with the C++ compiler. However, there may be errors or warnings when some C specific syntax is not supported by C++. If the C files contain no C++ code you may let them still compiled as C.
Using Cygwin is just like using any other C library. An example is the standard C library which functions are commonly called from C++ (e.g. all the strXXX functions).
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Jochen - thanks for discussing, this is driving me crazy. Shall I try compiling .CPP file as .C files once ?
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Member 10403830 wrote: You mean I should try compiling .CPP file as .C files once ? No.
That won't work. Just compile them first as they are (the MS compilers uses the file extension to select the compiler). If you have problems with C files, try to compile them as C++.
The errors from the C++ files must be solved by you to make the new MS compilers happy. If you get stuck with a specific error, ask here again showing the full error message, the code around the indicated line number, and the definitions of user defined types (e.g. structs and typedefs) if necessary.
Note that the errors may be also located in lines before the indicated one. Therefore always have also a look at the previous lines (especially the one before).
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Jochen, If you have a moment can you please have a look at this thread at msdn :
http://social.msdn.microsoft.com/Forums/en-US/e68b0af5-ed25-4953-80e7-e88463149b77/fatal-error-1017-invalid-integer-constant-expression-in-ctypeh-during-migration-from-vs6-to-vs5?forum=vcgeneral[^]
I tried that.Error from .cpp files are in thousands...they are of type
: error C2065: ‘xyz’: undeclared identifier
: error C2182: ‘pqr’ : illegal use of type 'void'
: error C2065: ‘some variable’ : undeclared identifier
: error C2146: syntax error : missing ';' before identifier ‘classname’
: error C2143: syntax error : missing ';' before '*'
: error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
: error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
: error C2040: ‘variable2’ : 'int *' differs in levels of indirection from ''unknown-type''
Removing them is manually one by one is the only way ? I am jsut trying to compile the code from visual studio 6 to visual studio 2006.
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Don't panic.
Most of the errors are sourced by previous ones. If you resolve one many other will vanish. So start always with the very first error for a source file and try to locate the reason. After fixing some errors you may discover that other errors are similar to the already fixed ones. So the work is not as much as expected at first glance.
If you don't get an error fixed post the relevant information here as said above.
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Jochen - to start with small fix at a time i took one .cpp file which has few errors. I removed __STDC__ as you said it should never be used with .CPP file. Without __STDC__ I got this error : cpp(53) : error C3646: 'DWORD' : unknown override specifier
xyz.cpp(53) : error C2143: syntax error : missing ';' before '__stdcall'
xyzcpp(53) : error C2065: 'somevariable' : undeclared identifier
xyz.cpp(54) : warning C4229: anachronism used : modifiers on data are ignored
xyz.cpp(54) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
xyz.cpp(54) : error C2365: 'abc_process' : redefinition; previous definition was 'function'
xyz.cpp(54) : error C2146: syntax error : missing ';' before identifier 'LPVOID'
.
.
These errors i tried to remove by adding relevant header files : #include <stdlib.h>,#include <windows.h>,#include <stdlib.h> None of them seems to have any effect on the Output , also tried to refer to these header files with the help of setting the path variable. will you please suggest if it needs any other settings or any other work around.
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As already mentioned: Focus on the very first error and ignore all others.
The first three errors are in line number 53 of the file xyz.cpp. So you should show us the content of that line and the previous line(s) (at least the line before containing code skipping empty and comment only lines) together with the real error messages (or is 'somevariable' really used there?).
To solve the error it may be also helpful to show us the declarations of any functions and types used in that lines that are not in the Windows header files (those decalred in your own or third party header files).
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It points to this code in XYZ.cpp :
#ifdef __STDC__
DWORD WINAPI process( LPVOID Var1)
#else
DWORD WINAPI process( Var1)
LPVOID Var1;
#endif
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