Govt Exams
volatile tells compiler that a variable's value may change unexpectedly and should not be optimized. It's often used for hardware registers.
Signed char uses 1 bit for sign, giving -128 to 127. Unsigned char uses all 8 bits for magnitude, giving 0 to 255.
C uses C-style casting with parentheses: (type) expression. This converts 5.7 to integer 5.
According to C99 standard, long long int is guaranteed to be at least 8 bytes (64 bits).
static variables are automatically initialized to 0 for numeric types and NULL for pointers if not explicitly initialized.
On 32-bit systems, int is typically 4 bytes (32 bits). However, the exact size is implementation-defined per C standard.
Variable names cannot start with a digit in C. Valid names must begin with a letter (a-z, A-Z) or underscore (_).
In standard C on 64-bit systems, double occupies 8 bytes and can store values with approximately 15-17 significant digits.
extern variables have global scope and exist throughout program execution. They can be accessed across multiple files.
The const keyword makes a variable read-only after initialization. Its value cannot be modified during program execution.