What is Static reallocation in C

 During the linker stage, the system has multiple object files to combine and it may be a possibility that some functions might have the same addresses so relocation or changing these addressing during combining the object file is called Static reallocation.

MultiLine Macros in C

Macros can be single line as well as multiline

for example :

#define AddMacro(x,y) \

{\

    int total = x + y; \

    printf("%d",total); \

}

In the above example \ is used to tell the compiler to consider the below lines too

if \ is missing then only the first line will be considered as Macro.

Toggle a bit in C using XOR

  

int number= 0b11001100;

void setup() {

  // put your setup code here, to run once:

  Serial.begin(9600);

}

void loop() {

  // put your main code here, to run repeatedly:

number ^= 1 << 2;

delay(100);

Serial.println(number,BIN);

}

since we count from zero the 3rd last bit will toggle

What is Stack overflow

  If a program accesses a memory beyond the available limit then a stack overflow occurs and the program gets terminated

C Language Interview Question:What is the use of "##" operator in C

  #include <stdio.h>

#define concat(a, b) a##b

int main(void)

{

    int yx =7;

    printf("%d\n", concat(y, x));

    printf("%d\n", concat(3, 2));

    return 0;

}

OUTPUT

7

32

EXPLAINATION

the ## operator will concatinate the parameters passed to the macro

In the first case

                            concat(y, x) - the macro will output yx and pass its value to printf as yx is treated as a variable by printf

In the second case

                            concat(3, 2) - the macro will output 32 and printf will print 32 as its treated as an integer

What is Segmentation fault

  Segmentation fault is a runtime fault caused due to invalid memory accesses

Segmentation fault can be caused in the following scenarios:

1. When a pointer points to an invalid address

2. When a program tries to access a read-only memory section

3. Freeing a memory which is already freed in the past

C controls- what is the output

  void main()

{

    int a = 2 ;

    float b = 2.0;

    if (a == b)

            printf("Hi");

}

OUTPUT

Hi

Explaination

the variable a is type casted to float before comparison