VC++ Interview Questions and Answers in 2025 (100+ Q&A)

System Integrator VC++

Ques:- What is the use of AFX_MANAGE_STATE ?

Asked In :-

Right Answer:
AFX_MANAGE_STATE is used in MFC (Microsoft Foundation Classes) to manage the state of the application when using a DLL. It ensures that the correct thread and module state is set up for the current thread, allowing the use of MFC features properly within the DLL.

System Integrator VC++

Ques:- What problem does the namespace feature solve?

Asked In :-

Right Answer:
The namespace feature solves the problem of name collisions by allowing developers to group identifiers (like classes, functions, and variables) into separate logical scopes, preventing conflicts between them.

System Integrator VC++

Ques:- What is the entry point for window based applications ?

Asked In :-

Right Answer:
The entry point for window-based applications is the `WinMain` function.

System Integrator VC++

Ques:- Export Restrictions

Asked In :-

Right Answer:
Export restrictions refer to regulations that limit or control the export of certain goods, technologies, or information from one country to another. These restrictions are often put in place for reasons related to national security, foreign policy, or economic protection.

System Integrator VC++

Ques:- What is the difference between struct and class?

Asked In :- Manabh Software,

Right Answer:
The main difference between struct and class in C++ is that members of a struct are public by default, while members of a class are private by default.

System Integrator VC++

Ques:- Explain about utility?

Asked In :-

Right Answer:
A utility in the context of software refers to a program or tool that performs a specific task to help manage, maintain, or control computer resources. Utilities can include file management tools, system monitoring applications, and other software that enhances the functionality of the operating system or applications.

System Integrator VC++

Ques:- Cmd Line Processing

Asked In :-

Right Answer:
Command line processing involves parsing and interpreting the arguments and options provided to a program when it is executed from a command line interface. This typically includes handling flags, options, and input parameters, allowing the program to execute specific functions based on user input. In VC++, this can be achieved using the `main` function's parameters `int argc` (argument count) and `char* argv[]` (argument vector) to access the command line arguments.

System Integrator VC++

Ques:- How to make the Activex auto download on the browser via cab file ?

Asked In :-

Right Answer:
To make an ActiveX control auto-download via a CAB file in a browser, you need to:

1. Create a CAB file containing your ActiveX control and any necessary files.
2. Use an HTML `<OBJECT>` tag to embed the ActiveX control in your webpage, specifying the `classid` and `codebase` attributes.
3. Set the `codebase` attribute to point to the location of the CAB file on your server.

Example:

```html
<object classid="clsid:YOUR-CLASS-ID"
codebase="http://yourserver.com/path/to/yourcontrol.cab#Version=1,0,0,0">
<param name="param1" value="value1">
<param name="param2" value="value2">
</object>
```

Make sure the browser settings allow ActiveX controls to be downloaded and installed.

System Integrator VC++

Ques:- : Are there any new intrinsic (built-in) data types?

Asked In :- WFP,

Right Answer:
Yes, in Visual C++, new intrinsic data types include `bool`, `wchar_t`, and `char16_t`/`char32_t` in C++11 and later standards.

System Integrator VC++

Ques:- What is CArchive class does?

Asked In :-

Right Answer:
The CArchive class in MFC (Microsoft Foundation Classes) is used for serializing and deserializing objects, allowing you to save and load data to and from files or memory. It provides a way to store complex data structures in a format that can be easily retrieved later.

System Integrator VC++

Ques:- What are all the situations where the /GS compiler is not applied.

Asked In :-

Right Answer:
The /GS compiler option is not applied in the following situations:

1. When compiling code with optimizations turned off (using /Od).
2. When compiling with certain compiler options that disable security checks, such as /sdl- (disabling Security Development Lifecycle checks).
3. In assembly language files or when using inline assembly.
4. When compiling code that does not contain any buffer or array usage that requires stack protection.
5. For certain legacy code or specific project settings that do not support /GS.

System Integrator VC++

Ques:- What You Should Include in a Header File

Asked In :-

Right Answer:
In a header file, you should include:

1. **Include Guards**: To prevent multiple inclusions.
2. **Function Declarations**: Prototypes of functions to be used.
3. **Class Definitions**: Definitions of classes and their members.
4. **Constants and Macros**: Definitions of constants and macro functions.
5. **Type Definitions**: Custom type definitions (e.g., typedefs, enums).
6. **Include Statements**: Necessary includes for other headers or libraries.

System Integrator VC++

Ques:- How to handle Varinat passed to COM components?

Asked In :-

Right Answer:
To handle a `VARIANT` passed to COM components in VC++, you can use the `VariantInit`, `VariantClear`, and `VariantCopy` functions from the Windows API. First, initialize the `VARIANT` using `VariantInit`. After using the `VARIANT`, clear it with `VariantClear` to free any resources. If you need to copy a `VARIANT`, use `VariantCopy`. Always ensure to check the `vt` (variant type) member to determine the actual data type before processing the value.

System Integrator VC++

Ques:- Explain about type_traits?

Asked In :-

Right Answer:
`type_traits` is a header in C++ that provides a set of templates to query and manipulate types at compile time. It includes features like checking if a type is integral, floating-point, or a pointer, and allows for type transformations such as removing constness or adding references. This is useful for template metaprogramming and enables more generic and type-safe code.

System Integrator VC++

Ques:- Explain about InitApplication()?

Asked In :-

Right Answer:
`InitApplication()` is a function in MFC (Microsoft Foundation Classes) that is called to perform application-wide initialization tasks. It is typically used to set up resources, register window classes, and perform any necessary configuration before the main application starts running. This function is usually overridden in the application class to implement custom initialization logic.

System Integrator VC++

Ques:- Redirecting Console Output

Asked In :-

Right Answer:
To redirect console output in VC++, you can use the `freopen` function to redirect `stdout` to a file. Here's an example:

```cpp
#include <cstdio>

int main() {
freopen("output.txt", "w", stdout); // Redirect stdout to output.txt
printf("This will be written to the file instead of the console.n");
fclose(stdout); // Close the file when done
return 0;
}
```

System Integrator VC++

Ques:- Visual C++

Asked In :-

Right Answer:
Visual C++ is an integrated development environment (IDE) from Microsoft for C and C++ programming languages, providing tools for developing Windows applications and software components.

System Integrator VC++

Ques:- Describe about unordered_map?

Asked In :-

Right Answer:
`unordered_map` is a C++ Standard Library container that stores key-value pairs in no particular order. It uses a hash table for fast retrieval, allowing average time complexity of O(1) for insertions, deletions, and lookups. Keys must be unique, and it allows for efficient access to elements based on their keys.

System Integrator VC++

Ques:- State some new features which are incorporated into Microsoft visual C++ 2008?

Asked In :- AnAr Solutions,

Right Answer:
Some new features in Microsoft Visual C++ 2008 include:

1. Support for the C++0x standard (now known as C++11) features.
2. Improved code editor with IntelliSense enhancements.
3. New Standard Template Library (STL) improvements.
4. Better integration with the .NET Framework.
5. Enhanced debugging tools and performance profiling.
6. Support for multi-core processors with parallel programming features.
7. Improved support for Windows Vista and Windows Server 2008.

System Integrator VC++

Ques:- HOW to Make ActiveX controls Safe for scripting/ Safe for Initialization

Asked In :-

Right Answer:
To make ActiveX controls Safe for Scripting and Safe for Initialization, you need to:

1. Implement the `ISupportErrorInfo` interface to provide error information.
2. Use the `IObjectSafety` interface to specify safety settings.
3. In the `IObjectSafety::SetInterfaceSafetyOptions` method, set the `INTERFACESAFE_FOR_UNTRUSTED_CALLER` and `INTERFACESAFE_FOR_UNTRUSTED_DATA` options.
4. Ensure that your control does not expose any methods or properties that could be unsafe when called from scripts.

This ensures that the ActiveX control can be safely used in web pages and other environments that require these safety measures.

Visual C++ (VC++) is a powerful and comprehensive development environment provided by Microsoft for the C++ programming language. It is a cornerstone of the Visual Studio suite and is specifically optimized to create high-performance, native applications for the Windows platform. While C++ is a general-purpose, cross-platform language, Visual C++ provides a complete and integrated toolchain that makes it the preferred choice for developers who require deep control over system resources and performance.

The VC++ environment is much more than just a compiler; it is an Integrated Development Environment (IDE) that offers a robust set of tools for every stage of the development process. This includes a sophisticated code editor with features like IntelliSense (for intelligent code completion), a powerful debugger for identifying and fixing errors, and profiling tools to analyze and optimize application performance. It also supports various Microsoft-specific libraries and frameworks, such as the Microsoft Foundation Classes (MFC) for building desktop applications and the Win32 API for direct interaction with the Windows operating system.

The primary strength of Visual C++ lies in its ability to generate highly optimized machine code, which is essential for applications where speed and efficiency are paramount. This makes it the go-to solution for a wide range of professional applications, including:

Video Games: The high performance and low-level control of VC++ are ideal for developing game engines and graphics-intensive software.
System-Level Programming: It is used for creating operating system components, device drivers, and other system-critical software.
High-Performance Computing: Applications in areas like financial modeling, scientific simulations, and high-frequency trading rely on VC++ for its raw speed.

In recent years, Visual C++ has expanded its capabilities to support cross-platform development, allowing developers to use the same powerful toolchain to build applications for Linux and other operating systems. In summary, Visual C++ combines the power and flexibility of the C++ language with a suite of professional-grade tools, making it an indispensable resource for building high-performance, native, and complex software.

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