This above figure shows two binary trees, but these binary trees are different. The first has an empty right subtree while the second has an empty left subtree. If the above are regarded as trees (not the binary trees), then they are same despite the fact that they are drawn differently. Also, an empty binary tree can exist, but there is no tree having zero nodes.
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38.
How do I use the function ldexp( ) in a program?

Ans: The math function ldexp( ) is used while solving the complex mathematical equations. This function takes two arguments, a double value and an int respectively. The order in which ldexp( ) function performs calculations is ( n * pow ( 2, exp ) ) where n is the double value and exp is the integer. The following program demonstrates the use of this function.

#include <stdio.h>
#include <math.h>

void main( )
{
double ans ;
double n = 4 ;

ans = ldexp ( n, 2 ) ;
printf ( "\nThe ldexp value is : %lf\n", ans ) ;
}
Here, ldexp( ) function would get expanded as ( 4 * 2 * 2 ), and the output would be the ldexp value is : 16.000000
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39.
Can we get the mantissa and exponent form of a given number?

Ans: The function frexp( ) splits the given number into a mantissa and exponent form. The function takes two arguments, the number to be converted as a double value and an int to store the exponent form. The function returns the mantissa part as a double value. Following example demonstrates the use of this function.

#include <math.h>
#include <stdio.h>

void main( )
{
double mantissa, number ;
int exponent ;

number = 8.0 ;
mantissa = frexp ( number, &exponent ) ;

printf ( "The number %lf is ", number ) ;
printf ( "%lf times two to the ", mantissa ) ;
printf ( "power of %d\n", exponent ) ;

return 0 ;
}
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40.

How do I write code that executes certain function only at program termination?
Ans: Use atexit( ) function as shown in following program.

#include <stdlib.h>
main( )
{
int ch ;
void fun ( void ) ;
atexit ( fun ) ;
// code
}
void fun( void )
{
printf ( "\nTerminate program......" ) ;
getch( ) ;
}
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41.
What are memory models?
Ans: The compiler uses a memory model to determine how much memory is allocated to the program. The PC divides memory into blocks called segments of size 64 KB. Usually, program uses one segment for code and a second segment for data. A memory model defines the number of segments the compiler can use for each. It is important to know which memory model can be used for a program. If we use wrong memory model, the program might not have enough memory to execute. The problem can be solved using larger memory model. However, larger the memory model, slower is your program execution. So we must choose the smallest memory model that satisfies our program needs. Most of the compilers support memory models like tiny, small, medium, compact, large and huge.