- What is programming language?
- Programming language is a pre-defined application.
- Programming language is standalone software.
- It is compatible to OS.
- What is the need of Programming language?
- Programming languages used to develop applications.
- Applications are used to communicate.
- Communication is the process of sharing information.
- What standalone application?
- Application which is compatible to Operating System.
- Application runs on single machine where it has installed.
- What is web application?
- Application run from different machines at a time.
- Application is independent to OS.
- Application run from the server machine.
- What is platform dependency?
- C and C++ languages are Platform dependent languages.
- Using C and C++, we can develop standalone applications.
- C compiler converts the source code into specific OS understandable instructions. Hence the compiled code can run on same OS is called Platform dependency.
- What is Platform in-dependency?
- Compiler converts the source code into the binary code which is understandable by different operating systems.
- Interpreter involves in Platform in-dependency.
- What is variable?
- Variable is the Identity of memory location.
- Variables are used to store the information.
- C language supports Local and Global variables.
- What is function?
- A block of instructions with an identity.
- Function is used to perform a task with logic.
- Function takes input(arguments), process and return result.
- Why program execution starts with main() function?
- Application is used in communication.
- Communication is possible with functionality.
- Hence every application program starts with a function.
- A standard function given to start communication with C program is called main() function.
- What is data type?
- In the declaration of variable, we need to specify its type.
- Data type describes the size of memory allocated to variable and what type of data is allowed to store into that memory.
- What are primitive data types?
- Primitive data types are pre-defined with fixed size.
- Examples are int, char, float….
- What is type casting?
- Conversion of data from one type to another type is called Casting.
- Type casting happens at runtime.
- What is sizeof() operator?
- A pre defined function also called Operator.
- It is used to find the size of data type variable, expression, array….
- What is the use of limits.h header file?
- Pre-defined header-file providing constant variables.
- These variables represent the limits (ranges) of each data type.
- What is operator?
- It is symbol.
- It performs operation on operands.
- Variables, Constants and Functions in Expression called OPERANDS.
- What is ternary operator?
- The operator performs operation of 3 operands.
- It is also called Conditional operator.
Syntax : Condition ? Expression1 : Expression2
- Differentiate Relational and Logical operators?
- Relational operators return a boolean value by validating operands in expression.
- Logical operators return a boolean value by validating more than one expression.
- What are shift operators?
- These are binary operators.
- These operators are used to move the binary bits in the memory.
- Operators are >> , <<
- What are assignment and Compound assignment operators?
- Assignment operator is used to assign value to variable.
- Compound assignment operators are modifying the value of variable.
- Operators are += , -= , *= , >>= …
- What is block?
- A block of instructions need to define with a keyword.
- Blocks cannot be called – no identity to call.
- Blocks like if, if-else are used to define a logic in the function.
- What is loop?
- A block of instructions need to define with a keyword.
- Loops cannot be called – no identity to call.
- Loops like while, for and do-while are used to define a logic in the function.
- When we use break, return and exit?
- Break statement is used to break the loop or switch case.
- Return statement is used to return the control from function.
- Exit statement is used to terminate the program execution.
- What is the use of continue?
- Continue statement is used to skip a particular iteration in loop execution.
- Explain goto in C?
- goto is a keyword.
- It is used to send the cursor from one place to another place in program using labels.
- What is stack memory?
- Functions and Blocks execute from stack memory.
- The memory allocate to execute a function in Stack is called Frame.
- Stack frame will be deleted once function execution completes.
- What is function prototype?
- Declaration of function by specifying arguments type and return type.
- Without prototype we cannot define and use a function in C program.
- What is function Definition and Call?
- Definition is a block of instructions which contains logic to perform a task.
- Function call is a single statement and it is used to access function logic.
- What is recursion?
- Function calling itself is called recursion.
- Calling the function from the definition of same function.
- What is array?
- It is a derived data type.
- It is used to store more than one element of same type.
- Array stores the values like student marks, mobile numbers….
- What is string?
- One dimensional character array
- Strings can be defined with double quotes.
- Strings are used to store values like names, address….
- What is pointer?
- A derived data type.
- Pointer variable stores the address of memory location.
- Pointers are called indirection operators.
- Pointers used to access the information of memory indirectly.
- What is the size of pointer?
- Pointer size is equals to the size of integer.
- Memory locations size depends on the type of compiler.
- 16 bit compiler contains 2^16 memory locations.
- Pointer stores an address hence the size is 2 bytes.
- How to access element in array using pointers?
- Using the concept of pointer arithmetic.
- For example if the array name is “arr” and index variable is “I”, we use *(arr+i) expression to access the elements of array.
- What is pointer modify?
- Increment/Decrement the value of pointer variable.
- It is also called pointer arithmetic.
- It is used to access the elements of array using pointers.
- What is call by value?
- Call by value is the concept of calling the function by passing values as parameters.
- We collect these values into arguments (local variables) of function.
- What is call by reference?
- Passing references of variables while calling the function.
- We collect these references into pointer type variables in called function.
- What is dangling pointer?
- A pointer variable that stores the address of another function local variables.
- Dangling pointer variables are used to get the instant results after function execution.
- What is structure?
- Structure is a user defined data type.
- Structure is used to store more than one element of different data types.
- Structures are used to store student, employee and account records data.
- What is the size of structure?
- Structure is a collection of elements of different data type
- Size of structure is equals to the sum of sizes of individual elements.
- Sizeof() operator can be used to find the size of structure type also.
- What is union?
- Unions were used in early days when memory at premium.
- Union is a user defined data type.
- Unions allowed to define more than one element but stores only one element at a time.
- What is the size of union?
- Size of union is equal to the size of element in that union occupies higher memory.
- What is static memory?
- Static memory represents fixed memory allocated to variables.
- Primitive data type’s size is static.
- C allows allocating both static and dynamic memory.
- What is dynamic memory?
- The concept of modifying the size of memory block at runtime depends on the data.
- How can we allocate memory dynamically?
- Stdlib.h header files providing pre-defined functionality to allocate memory dynamically in C language.
- Explain malloc() function
- Predefined function belongs to stdlib.h
- It is used to allocate the memory dynamically to structures using pointers.
- Malloc() function takes size as an input.
- Malloc() function returns void* type after allocating the memory.
- If the memory is not available, returns NULL pointer.
- What are calloc() and realloc() functions?
- Pre-defined functions belongs to stdlib.h
- Calloc() allocate memory dynamically to arrays.
- Calloc() allocate fixed size initially.
- Realloc() function is used to increase or decrease the size of array allocated by calloc().
- What is the use of free() function?
- Function belongs to stdlib.h
- It is used to release the memory which is allocated by calloc() or malloc().
- Free() function intimates the executor about the memory which in not in use with specific pointer so that can be allocated to other variable.
- What is typedef?
- It is a keyword.
- It is user defined data type.
- It is used to create synonyms to existing data types.
- These synonyms do not occupy memory and these are not permanent data types.
- What is enum?
- It is a keyword.
- It is a user defined data type.
- It is used to create set of elements assigned with constant integer values.
- We can perform set operations using enumeration.
- Explain the use of storage classes?
- In the declaration of variable we need to specify storage class along with data type.
- Storage class representation is optional.
- C storage classes are auto, static, register and extern.
- Storage classes provide information about storage location, default value, scope and availability of variable.
