Write about Nesting of Functions?

C performs nesting of functions freely main can call function 1, which call function 2; which calls function 3,……….. And so on.

Syntax : 

main ( )
{
…….
…….
fn 1( );
}
float fn1( )
{
……..
……..
fn 2( );
}
 int fn2( )
{
……
.…..
}


Ex: 

float ratio ( int x, int y, int z);
int diff ( int x, int y);
main ( )
{
int a, b, c;
scanf (“%d%d%d”, & a&b&c);
printf (“%f \n “, ratio (a,b,c));
}

float ratio ( int x, int y, int z)
{
if ( diff (y,z))
return ( x/(y-z));
else
return ( 0,0);
}

int diff ( int p, int q)
{
if ( p! = q)
return ( 1);
else
return ( 0);
}

Nesting of function calls is also possible.

Ex:  P = mul ( mul (5,2),6);

The inner function call is evaluated first and the returned value is again used as an actual argument in the outer function call.