Sizeof Operator in C Programming Language

Lets write a C program to see how to use sizeof() method or function in C programming language.

sizeof() is a builtin method/function present in C programming. It is used to calculate the size(in bytes) that a datatype occupies in the computers memory.

sizeof() method takes a single argument and it is not a function whose value is determined at run time, but rather an operator whose value is determined by compiler – so it’s called as compile time unary operator.

sizeof() method can be used with primitive data type like int, float, char or user defined data types like structures, unions etc.

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Source Code: Sizeof Operator in C Programming Language

  1. #include < stdio.h >  
  2.   
  3. int main()  
  4. {  
  5.     int a, a1[10];  
  6.     char s;  
  7.     char s1[10];  
  8.     int b = 10, c = 5;  
  9.   
  10.     printf("Size of a single character is %d byes\n"sizeof(s));  
  11.     printf("Size of a character array s1[10] is %d byes\n"sizeof(s1));  
  12.     printf("Size of a integer is %d byes\n"sizeof(a));  
  13.     printf("Size of a long integer is %d byes\n"sizeof(long int));  
  14.     printf("Size of a long long integer is %d byes\n"sizeof(long long int));  
  15.     printf("Size of a integer array a1[10] is %d byes\n"sizeof(a1));  
  16.     printf("Size of a float is %d byes\n"sizeof(float));  
  17.     printf("Size of a double is %d byes\n"sizeof(double));  
  18.     printf("Size of a long double is %d byes\n"sizeof(long double));  
  19.     printf("Size of a b+c is %d byes\n"sizeof(b+c));  
  20.   
  21.     return 0;  
  22. }  

Output:
Size of a single character is 1 byes
Size of a character array s1[10] is 10 byes
Size of a integer is 4 byes
Size of a long integer is 4 byes
Size of a long long integer is 8 byes
Size of a integer array a1[10] is 40 byes
Size of a float is 4 byes
Size of a double is 8 byes
Size of a long double is 12 byes
Size of a b+c is 4 byes

short, int, long int, long long int

  1. #include < stdio.h >  
  2.   
  3. int main()  
  4. {  
  5.     printf("Size of short data type is %d\n"sizeof(short));  
  6.     printf("Size of integer data type is %d\n"sizeof(int));  
  7.     printf("Size of long integer data type is %d\n"sizeof(long int));  
  8.     printf("Size of long long integer data type is %d\n"sizeof(long long int));  
  9.   
  10.     return 0;  
  11. }  

Output:
Size of short data type is 2
Size of integer data type is 4
Size of long integer data type is 4
Size of long long integer data type is 8

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