Interview :: C
C is a mid-level and procedural programming language. The Procedural programming language is also known as the structured programming language is a technique in which large programs are broken down into smaller modules, and each module uses structured code. This technique minimizes error and misinterpretation.
C is known as a mother language because most of the compilers and JVMs are written in C language. Most of the languages which are developed after C language has borrowed heavily from it like C++, Python, Rust, javascript, etc. It introduces new core concepts like arrays, functions, file handling which are used in these languages.
The main features of C language are given below:
- Simple: C is a simple language because it follows the structured approach, i.e., a program is broken into parts
- Portable: C is highly portable means that once the program is written can be run on any machine with little or no modifications.
- Mid Level: C is a mid-level programming language as it combines the low- level language with the features of the high-level language.
- Structured: C is a structured language as the C program is broken into parts.
- Fast Speed: C language is very fast as it uses a powerful set of data types and operators.
- Memory Management: C provides an inbuilt memory function that saves the memory and improves the efficiency of our program.
- Extensible: C is an extensible language as it can adopt new features in the future.
printf(): The printf() function is used to print the integer, character, float and string values on to the screen.
Following are the format specifier:
- %d: It is a format specifier used to print an integer value.
- %s: It is a format specifier used to print a string.
- %c: It is a format specifier used to display a character value.
- %f: It is a format specifier used to display a floating point value.
scanf(): The scanf() function is used to take input from the user.
Following are the differences between a local variable and global variable:
| Basis for comparison | Local variable | Global variable |
|---|---|---|
| Declaration | A variable which is declared inside function or block is known as a local variable. | A variable which is declared outside function or block is known as a global variable. |
| Scope | The scope of a variable is available within a function in which they are declared. | The scope of a variable is available throughout the program. |
| Access | Variables can be accessed only by those statements inside a function in which they are declared. | Any statement in the entire program can access variables. |
| Life | Life of a variable is created when the function block is entered and destroyed on its exit. | Life of a variable exists until the program is executing. |
| Storage | Variables are stored in a stack unless specified. | The compiler decides the storage location of a variable. |
Following are the uses of a static variable:
- A variable which is declared as static is known as a static variable. The static variable retains its value between multiple function calls.
- Static variables are used because the scope of the static variable is available in the entire program. So, we can access a static variable anywhere in the program.
- The static variable is initially initialized to zero. If we update the value of a variable, then the updated value is assigned.
- The static variable is used as a common value which is shared by all the methods.
- The static variable is initialized only once in the memory heap to reduce the memory usage.
Uses of C function are:
- C functions are used to avoid the rewriting the same code again and again in our program.
- C functions can be called any number of times from any place of our program.
- When a program is divided into functions, then any part of our program can easily be tracked.
- C functions provide the reusability concept, i.e., it breaks the big task into smaller tasks so that it makes the C program more understandable.