About sizeof() operator in C Language

size of : -

It is a operator can keyword in ‘c’ language

• it is a urinary operator which returns size of even argument.
• size of operator always returns unsigned integer value only and which value is greater than “Zero”

void main()

{

int i;

char ch;

float f;

printf("\n size of int %d”, sizeof(i));

printf(“\n size of char: %d ”, sizeof ch);

printf(“\n size of float : %d”, size of F);

}

o/p: size of int : 2

size of char:1

size of float:4

sizeof(int)           2 bytes

sizeof(signed)    2 bytes

sizeof(short)     2

sizeof(long)    4

sizeof(25)     2

sizeof(40000u)    2

sizeof(655361)    4

sizeof(char)    1

sizeof(‘A’)     2              // sizeof(65) --- >2

char ch;

ch=’A’;

sizeof(ch)  1

size of character or character variable is 1 byte but the size of character constant is 2 bytes, because by default character constant returns integer value. i.e ‘ASCII’  value of a character. So, we will get 2 bytes

sizeof(ch)     1

sizeof(float)  4

sizeof(double)  8

sizeof(long double)  -   10

sizeof(short double)    error

sizeof(12.8)     8 //double

sizeof(12.8f)    4   //float

sizeof(12.8L)   10    // long double

sizeof(3.0)     8

sizeof(3.5)   8

void main()

{

int i;

i=0;

printf(“\nsize1:%d”, size(i));

printf(“\nsize2:%d”, size(i*1 5l));

printf(“\nsize3:%d”, size(i/2.0));

printf(“\nsize4:%d”, size(i/2.0f));

printf(“\nsize5:%d”, size(i=i*15));

printf(“\ni=%d”,i);

o/p :

size1         :        2       //int

Size2    :        4       // int,long  long

size3     :        8       //int,double  double

size4     :        4       //int, float    float

size 5     :        2       //int,int         int

i=0

in size of operator all expressions can be evaluated except assignment.

void main()

{

int a;

a=10;

printf(“\n size of a: %d”, sizeof(++a));     //a=a+1   ignore inclure

printf(“/n a=%d”,a);

}

o/p : size of a:2

a=10