Wabtec Interview Questions and Answers

Input and output functions in C language are used to interact with the user and the external environment.

• Input functions in C include scanf() for reading input from the user and getchar() for reading a single character.

• Output functions in C include printf() for displaying output to the user and putchar() for displaying a single character.

• File input and output functions in C include fopen(), fclose(), fread(), and fwrite() for reading from and writing to files.

Header files contain declarations of functions, variables, and constants used in a program.

• Header files are included in source code files using #include directive.

• They help in organizing code by separating declarations from implementation.

• Common header files in C/C++ include , , and .

There are mainly four types of databases: relational, NoSQL, object-oriented, and graph databases.

• Relational databases: store data in tables with rows and columns (e.g. MySQL, PostgreSQL)

• NoSQL databases: store data in non-tabular format, suitable for large amounts of data (e.g. MongoDB, Cassandra)

• Object-oriented databases: store data as objects, allowing for complex data structures (e.g. db4o)

• Graph databases: store data in nodes and edges to represent relationships (e.g. Neo4...read more

Datatypes in C language include int, float, char, double, and more.

• Basic datatypes: int, float, char, double

• Derived datatypes: arrays, pointers, structures, unions

• Enumerated datatypes: enum

• Void datatype: void

• Example: int num = 10; char letter = 'A'; float value = 3.14;

A database is a structured collection of data that is organized in a way to easily access, manage, and update information.

• Database stores data in tables with rows and columns.

• It allows for efficient retrieval, insertion, and updating of data.

• Examples include MySQL, PostgreSQL, MongoDB.