Do i have to check for null after p = new fred()?, C/C++ Programming

Assignment Help:

A: No. (Excluding if you have an old compiler, you might have to force the new operator to throw an exception if it runs out of memory.)

This turns out to be a real pain to always write down explicit NULL tests after each new allocation. Code like the following is extremely tedious:

Fred* p = new Fred();

if (p == NULL)

throw std::bad_alloc();

If your compiler doesn't support (or if you reject to use) exceptions, your code may be even more tedious:

Fred* p = new Fred();

if (p == NULL) {

std::cerr << "Couldn't allocate memory for Fred" << std::endl;

abort();

}

In C++, if the runtime system can't allocate sizeof(Fred) bytes of memory throughout p

= new Fred(), a std::bad_alloc exception will thrown. Unlike malloc(), new never returns

NULL!

Then you should simply write:

Fred* p = new Fred(); // No require to check if p is NULL

Though, if your compiler is old, it might not yet support this. Determine by checking your compiler's documentation under "new". If you hold an old compiler, you might have to force the compiler to have this behavior.

 

Note: If you are using Microsoft Visual C++, to obtain new to throw an exception while it fails you have to #include some standard header in at least one of your .cpp files. For instance, you could

#include (or or or ...).

 

 


Related Discussions:- Do i have to check for null after p = new fred()?

C++ programming, Write a program to convert English units to metric (e.g., ...

Write a program to convert English units to metric (e.g., miles to kilometers, gallons to liters, etc.). Include a specification and a code design.

Define functions with arguments and return values, Define Functions with ar...

Define Functions with arguments and return values? The earlier category functions receive values from the calling function through arguments but do not send back any value rath

Advanced features of c, We are now quite happy to use the basic mathematica...

We are now quite happy to use the basic mathematical expressions, however in engineering we use scientific functions i.e Sin , Cos  , ln etc . Within C we have the following functi

Define types of storage classes in c language, Define Types of storage clas...

Define Types of storage classes in C language? There are four storage classes in C language: 1. Automatic storage class. 2. External storage class. 3. Register storage cla

Determine the size of an interger data type without using , Determine the s...

Determine the size of an interger data type without using sizeof() function? A: #include int main() { int *i ; int *j = i + 1; cout }

Write a program to illustrate array with strings, Write a Program to illust...

Write a Program to illustrate Array with Strings? main() { static char name[]="devdas"; int i; i=0; while(name[i]!='\0') { printf("%c",name[i]); i=i+1; } } In the

Simple program of c++ , Simple program of c++: int main() {    i...

Simple program of c++: int main() {    int   bushels;    float dollars, rate;                 cout                 cin >> dollars;                 cout

Is it possible to pass an entire structure to functions, Is it possible to ...

Is it possible to pass an entire structure to functions? Yes, it's possible to pass an entire structure to a function in a call by method style. Some programmers prefer to decl

Define procedure to input integers and returns the average, The procedure +...

The procedure +, * and list take arbitrary numbers of arguments. One way to define such a procedure is to use define with dotted-tail notation. In a procedure definition, a paramet

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd