What does sizeof do in c language?

sizeof is an operator in C language that obtains the byte size of a variable. Its usage is size_t sizeof(argument). argument can be a variable name, data type or expression. The role of sizeof includes managing memory, handling data structures, type checking, and implementing cross-platform code.

The role of sizeof in C language

sizeof is a C language operator used to obtain variables or The size in bytes of the data. It is a unary operator, and the operand can be a variable name, data type or expression.

Usage

size_t sizeof(argument);

Among them, argument can be:

• Variable name: Return the words occupied by the variable Section number.
• Data type: Returns the number of bytes occupied by variables of this data type.
• Expression: Returns the number of bytes occupied by the expression result.

Return type

The sizeof operator returns a size_t type value, representing the byte size of the data or expression.

Function

The sizeof operator mainly has the following functions in C language:

• Manage memory: Through sizeof operator, you can know the byte size of a variable or data to avoid errors when allocating memory.
• Processing data structures: The sizeof operator can help determine the memory layout of the structure or union to facilitate data access and manipulation.
• Type checking: With the sizeof operator, you can check the type of a variable or expression to ensure that it meets the intended use.
• Implementing cross-platform code: Variables and data structures on different platforms may have different byte sizes. By using the sizeof operator, you can write cross-platform code that runs on different platforms.

Example

int main() {
  int a = 10;
  double b = 3.14;

  printf("Size of int a: %zu bytes\n", sizeof(a));
  printf("Size of double b: %zu bytes\n", sizeof(b));

  return 0;
}

Output:

<code>Size of int a: 4 bytes
Size of double b: 8 bytes</code>

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