Why does sizeof(x++) not Increment x in C

Sizeof() is a much-involved operator in C or C++. It is an incorporated time unary administrator which can be utilized to figure the size of its operand. The consequence of size is of the unsigned fundamental sort, normally signified by size_t. sizeof() operator can be applied to any information type, including crude sorts, for example, whole number and drifting point types, pointer types, or compound datatypes, for example, Structure, union, and so on.

• When the operand is a Data Type:

When sizeof() is utilized with the information types, for example, int, float, scorch… and so on, it returns how much memory is apportioned to that data type.

Example:

//simple C program to check the size of the data types using the sizeof() //operator
#include <conio.h>   //here, we are including the console input and output //library into our program
#include <stdio.h>   //here, we are including the standard input and output //library into our program
int main()
{
    clrscr();
    printf(“Printing the size of data types using the sizeof() operator:”);
    printf("The size of the char data type is %lu\n", sizeof(char));    //here, we //are printing the size of char data type using the sizeof() operator
    printf("The size of the char data type is %lu\n", sizeof(int));      //here, we //are printing the size of integer data type using the sizeof() operator
    printf("The size of the char data type is %lu\n", sizeof(float));   //here, we //are printing the size of float data type using the sizeof() operator
    printf("The size of the char data type is %lu", sizeof(double));    //here, we //are printing the size of double data type using the sizeof() operator
    return 0;
}

Output:

Printing the size of data types using the sizeof() operator:
The size of the char data type is 1
The size of the char data type is 4
The size of the char data type is 4
The size of the char data type is 8

• When the operand is an expression

When sizeof() is utilized with the expression, it returns the size of the expression.

Example:

//simple C program to check the size of the data types using the sizeof() //operator
#include <conio.h>   //here, we are including the console input and output //library into our program
#include <stdio.h>   //here, we are including the standard input and output //library into our program
int main()
{
    int n =0;     //here, we are declaring the integer variable with the value 0 
    double d = 22.15;    //here, we are declaring the double variable with the //value 22.15 
    printf(“Printing the size of the given expression using the sizeof() operator:”);
    printf("The size of the given expression is %lu\n", sizeof(n + d));    //here, we //are printing the size of char data type using the sizeof() operator
    return 0;
}

Output:

Printing the size of the given expression using the sizeof() operator:
The size of the given expression is 8

Why does sizeof(x++) not Increment x in C?

The sizeof() administrator considers the kind of the operand, which might be an articulation or the name of a sort (i.e, int, twofold, float, and so forth), and not the worth got on assessing the articulation. Subsequently, the operand inside the sizeof() administrator isn't assessed. It is assessed provided that the kind of the operand is variable length exhibited on the grounds that, all things considered, the size can be resolved solely after the articulation is assessed.

Case 1:

When the sizeof() method is passed a fixed size structure:

In this situation, the sizeof() administrator doesn't assess the boundary. Just the sort of boundary is checked, and its size is returned.

Example:

//simple C program to check the size of the data types using the sizeof() //operator
#include <conio.h>   //here, we are including the console input and output //library into our program
#include <stdio.h>   //here, we are including the standard input and output //library into our program
int main()
{
    int n = 10;       //here, we are declaring the integer variable with the data 3 
    printf("The size of the given variable is %d\n", sizeof(n++));      //here, we are //printing the value of the n after incrementing
    printf("The given data of the variable is n = %d", n);     //here, we are printing the //original value of the n
    return 0;
}

Output:

The size of the given variable is 11
The given data of the variable is n = 10

Explanation:

The result worth of x after augmentation is as yet 10 when contrasted with the average worth, which is 11. This is because the sizeof administrator doesn't have to assess the articulation to acquire the size as the information kind of the operand doesn't change, and thus the size continues as before.

Case 2:

When the sizeof() method is passed a variable size structure:

For this situation, the sizeof() administrator assesses the boundary to check whether there is any difference in size. In the event that it is found, first, the size is altered, then the last size is returned.

Example:

//simple C program to check the size of the data types using the sizeof() //operator
#include <conio.h>   //here, we are including the console input and output //library into our program
#include <stdio.h>   //here, we are including the standard input and output //library into our program
int main()
{
    int n = 10;       //here, we are declaring the integer variable with the data 3 
    printf("The size of the given variable is %d\n", sizeof(int[n++]));      //here, we are //printing the value of the n after incrementing
    printf("The given data of the variable is n = %d", n);     //here, we are printing the //original value of the n
    return 0;
}

Output:

The size of the given variable is 40
The given data of the variable is n = 10

Explanation:

In this model, the sizeof administrator requirements to assess the articulation to ascertain the size of the exhibit, which is displayed in the figure. Thus, for this situation, we get the worth of n after incrementation.

Example 1:

//simple C program to check the size of the data types using the sizeof() //operator
#include <conio.h>   //here, we are including the console input and output //library into our program
#include <stdio.h>   //here, we are including the standard input and output //library into our program
int main()
{
    int n = 10;       //here, we are declaring the integer variable with the data 3 
    printf("The size of the given variable is %d\n", sizeof(int[n++]));      //here, we are //printing the value of the n after incrementing
    printf("The given data of the variable is n = %d", n);     //here, we are printing the //original value of the n
    return 0;
}

Output:

The size of the given variable is 44
The given data of the variable is n = 10

Explanation:

Again in this example, the sizeof administrator requirements to assess the articulation to ascertain the size of the exhibit, which is displayed in the figure. In this model, the post-increase administrator is utilized, and the result in the main line is 44. In the subsequent line, the worth of x is printed after incrementation.