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Top Forums Programming Class Pointer initialization C++ Post 302519627 by sidorenko on Wednesday 4th of May 2011 12:20:16 PM
Old 05-04-2011
as far as I remember, in
Code:
ClassA * point;
point = new ClassA;

`new' will allocate memory for exactly one object of type `ClassA' and yield the address of the 1-st memory cell at which the definition of the object will start. In
Code:
ClassA *point;
point = 0;

you're not creating any object at all but just explictily stating that the pointer `point' will point to the zero-th cell. In that case your pointer merely becomes the so called `null pointer' - a special kind of pointers which do not point to any valid memory address.

I might err, so please correct me, if I'm wrong

---------- Post updated at 11:20 AM ---------- Previous update was at 11:20 AM ----------

as far as I remember, in
Code:
ClassA * point;
point = new ClassA;

`new' will allocate memory for exactly one object of type `ClassA' and yield the address of the 1-st memory cell at which the definition of the object will start. In
Code:
ClassA *point;
point = 0;

you're not creating any object at all but just explictily stating that the pointer `point' will point to the zero-th cell. In that case your pointer merely becomes the so called `null pointer' - a special kind of pointers which do not point to any valid memory address.

I might err, so please correct me, if I'm wrong
 

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CHECKOBJ(1)						      General Commands Manual						       CHECKOBJ(1)

NAME
checkobj - check an object file to see whether it can be executed SYNTAX
checkobj [ -s ] [ -f ] [ -40 ] [ file ... ] DESCRIPTION
Checkobj attempts to determine whether the named files are valid executable binary files. It checks for size restrictions, including those due to the granularity of memory management on the PDP11. It is especially useful for overlaid object files, where there are a number of constraints. If a file is too large or improperly laid out, checkobj attempts to point out format changes that would allow the program to run. OPTIONS
Several options control the checks: -s Check for the use of separate I/D. If the file is separate executable, an error is flagged, and an appropriate way to load for a nonseparate machine is suggested if possible. -f Check for the use of floating point arithmetic without inclusion of the floating-point interpreter. -40 Combine the -s and -f options, to check for suitability for an 11/40-class PDP11. BUGS
The test for floating point is simple-minded. It is based on the definition of ``fltused'' by the C compiler and ``fptrap'' in the float- ing-point simulator. This test does not work if the object has been stripped. DIAGNOSTICS
The exit status is 0 if all named files are runnable with the specified options, nonzero otherwise. AUTHOR
Mike Karels, University of California, Berkeley 3rd Berkeley Distribution CHECKOBJ(1)
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