How to calculate sizeof in c language

The sizeof operator in C language gets the number of bytes of a data type or variable. It can act on data types, variable names, array names, structure or union types. The returned value is the number of bytes occupied by the data type or variable, in bytes. It is used to determine memory allocations, calculate array or structure sizes, verify data type compatibility, and implement portable code.

Usage of sizeof in C language

sizeof is An operator in C language used to obtain the number of bytes occupied by a data type or variable in memory. It returns an integer in bytes.

Usage

sizeof is followed by a parentheses, which can be:

• data type (for example :sizeof(int))
• Variable name (for example: sizeof(myVariable))
• Array name (the array name is the first element of the array Address, for example: sizeof(myArray))
• Structure or union type (for example: sizeof(myStructure))

Return value

sizeof The returned value is the number of bytes occupied by the data type or variable in memory. For example, on 32-bit systems, sizeof(int) usually returns 4 because the int type occupies 4 bytes.

Uses

sizeof has many uses, including:

• Determine the amount of memory allocated
• Calculate the size of an array or structure
• Verify whether the data types are compatible
• Implement portable code (get the same results on different platforms)

Example

<code class="c">#include <stdio.h>

int main() {
  printf("int size: %ld\n", sizeof(int));
  printf("float size: %ld\n", sizeof(float));
  printf("double size: %ld\n", sizeof(double));
  printf("char size: %ld\n", sizeof(char));

  int myVariable = 123;
  printf("myVariable size: %ld\n", sizeof(myVariable));

  return 0;
}</code>

Output:

<code>int size: 4
float size: 4
double size: 8
char size: 1
myVariable size: 4</code>

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