Technical interview questions and answers are essential for clearing a C Language Interview because C is the foundation of all modern programming languages. C interviews typically include questions related to pointers, loops, functions, arrays, memory allocation, structures, and file handling. Whether you are preparing for campus placements or software development roles, companies such as TCS, Wipro, Infosys, Cognizant, and Accenture frequently test your C programming basics. This guide includes the most frequently asked C Language interview questions with clear explanations to help freshers and job seekers build strong conceptual understanding. Learning these questions will help you perform confidently in coding rounds, written tests, and technical interviews.
C programmers should advance their skills by learning C++ programming and mastering data structures for algorithm development
Showing 10 of 130 questions
51. What does static variable mean?
Static variables are the variables which retain their values between the function calls. They are initialized only once their scope is within the function in which they are defined.
52. What is a pointer?
Pointers are variables which stores the address of another variable. That variable may be a scalar (including another pointer), or an aggregate (array or structure). The pointed-to object may be part of a larger object, such as a field of a structure or an element in an array.
53. What is a structure?
Structure constitutes a super data type which represents several different data types in a single unit. A structure can be initialized if it is static or global.
54. What is a union?
Union is a collection of heterogeneous data type but it uses efficient memory utilization technique by allocating enough memory to hold the largest member. Here a single area of memory contains values of different types at different time. A union can never be initialized.
55. What are the differences between structures and union?
A structure variable contains each of the named members, and its size is large enough to hold all the members. Structure elements are of same size.
A union contains one of the named members at a given time and is large enough to hold the largest member. Union element can be of different sizes.
56. What are the differences between structures and arrays?
tructure is a collection of heterogeneous data type but array is a collection of homogeneous data types
57. In header files whether functions are declared or defined?
Functions are declared within header file. That is function prototypes exist in a header file,not function bodies. They are defined in library (lib).
58. What are the differences between malloc () and calloc ()?
Malloc Calloc 1-Malloc takes one argument Malloc(a);where a number of bytes 2-memory allocated contains garbage values
1-Calloc takes two arguments Calloc(b,c) where b no of object and c size of object
2-It initializes the contains of block of memory to zerosMalloc takes one argument, memory allocated contains garbage values.
It allocates contiguous memory locations. Calloc takes two arguments, memory allocated contains all zeros, and the memory allocated is not contiguous.
59. What are macros? What are its advantages and disadvantages?
Macros are abbreviations for lengthy and frequently used statements. When a macro is called the entire code is substituted by a single line though the macro definition is of several lines.
The advantage of macro is that it reduces the time taken for control transfer as in case of
function.
The disadvantage of it is here the entire code is substituted so the program becomes
lengthy if a macro is called several times.
60. Difference between pass by reference and pass by value?
Pass by reference passes a pointer to the value. This allows the callee to modify the variable directly.Pass by value gives a copy of the value to the callee. This allows the callee to modify the value without modifying the variable. (In other words, the callee simply cannot modify the variable, since it lacks a reference to it.)