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Full Discussion: Compiler error "lvalue required as left operand of assignment"
Homework and Emergencies Homework & Coursework Questions Compiler error "lvalue required as left operand of assignment" Post 302700935 by Corona688 on Friday 14th of September 2012 12:08:26 PM
Old 09-14-2012
Just to make the error plain:

Code:
else if ((sqrt((dx2*dx2)+(dy2*dy2))>=b),(sqrt((dx3*dx3)=(dy3*dy3))>=c),(sqrt((dx1*dx1)+(dy1*dy1))<=a))

I should point out, though, that == doesn't work very well with floating point either. It will be extremely picky. Is 3.000001 equal to 3.000002? No. Only 3.0000001000 will be exactly the same as 3.0000001000. There's also the problem that the same number can appear in several different ways in floating point.

So don't check if floats are equal. Check if they're "close enough" by subtracting them, taking the absolute value, and seeing if the result is less than the maximum distance apart you want:

Code:
#include <math.h>

bool isequal(double a, double b, double accuracy)
{
        return(fabs(a-b)<=accuracy);
}

int main(void)
{
        double a=9.00001, b=9.00002;
        cout << "Equal to 0.00000001 precision? " << isequal(a, b,   0.00000001) <<endl;
        cout << "Equal to 0.0001 precision? " << isequal(a, b,   0.0001) << endl;
}

 

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LEARN ABOUT NETBSD

type

type(1) 							   User Commands							   type(1)

NAME

       type - write a description of command type

SYNOPSIS

       type name...

DESCRIPTION

       The  type  utility  indicates how each name operand would be interpreted if used as a command. type displays information about each operand
       identifying the operand as a shell built-in, function, alias, hashed command, or keyword, and where applicable, may display  the  operand's
       path name.

       There is also a shell built-in version of type that is similar to the type utility.

OPERANDS

       The following operand is supported:

       name	A name to be interpreted.

ENVIRONMENT VARIABLES

       See  environ(5)	for descriptions of the following environment variables that affect the execution of type: LANG, LC_ALL, LC_CTYPE, LC_MES-
       SAGES, and NLSPATH.

       PATH	Determine the location of name.

EXIT STATUS

       The following exit values are returned:

       0	Successful completion.

       >0	An error occurred.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       typeset(1), attributes(5), environ(5), standards(5)

SunOS 5.10							    1 Feb 1995								   type(1)
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