C# Interview Questions and Answers For Freshers Part-1
1.What is C#?
C# is a modern, general-purpose, object-oriented programming language developed by Microsoft. C# is designed for Common Language Infrastructure (CLI), which consists of the executable code and runtime environment that allows use of various high-level languages on different computer platforms and architectures.
2.In how many ways you can pass parameters to a method?
There are three ways that parameters can be passed to a method −
Value parameters − This method copies the actual value of an argument into the formal parameter of the function. In this case, changes made to the parameter inside the function have no effect on the argument.
Reference parameters − This method copies the reference to the memory location of an argument into the formal parameter. This means that changes made to the parameter affect the argument.
Output parameters − This method helps in returning more than one value.
3.Can you return multiple values from a function in C#?
Yes! Using output parameters. A return statement can be used for returning only one value from a function. However, using output parameters, you can return two values from a function.
4.What is the difference between ref and out parameters?
Output parameters are similar to reference parameters, except that they transfer data out of the method rather than into it. Reference parameter copies the reference to the memory location of an argument into the formal parameter. This means that changes made to the parameter affect the argument.
5.What is namespace in C#?
A namespace is designed for providing a way to keep one set of names separate from another. The class names declared in one namespace does not conflict with the same class names declared in another.
6.What is the purpose of using statement in C#?
using keyword is used to include a namespace in the program. A program generally has multiple using statements.
7.What are value types in C#?
Value type variables can be assigned a value directly. They are derived from the class System.ValueType.
The value types directly contain data. Some examples are int, char, and float, which stores numbers, alphabets, and floating point numbers, respectively. When you declare an int type, the system allocates memory to store the value.
8.What are reference types in C#?
The reference types do not contain the actual data stored in a variable, but they contain a reference to the variables.
In other words, they refer to a memory location. Using multiple variables, the reference types can refer to a memory location. If the data in the memory location is changed by one of the variables, the other variable automatically reflects this change in value. Example of built-in reference types are: object, dynamic, and string.
9.Which class acts as a base class for all the data types in .net?
The Object Type is the ultimate base class for all data types in C# Common Type System (CTS). Object is an alias for System.Object class. The object types can be assigned values of any other types, value types, reference types, predefined or user-defined types. However, before assigning values, it needs type conversion.
10.What are virtual functions in C#?
When you have a function defined in a class that you want to be implemented in an inherited class(es), you use virtual functions. The virtual functions could be implemented differently in different inherited class and the call to these functions will be decided at runtime.