L-Value in Expression : L-value require Error [Solved]

What is LValue ?

1. Lvalue stands for left value and Expressions that refer to memory locations are called “l-value” expressions.
2. In any Assignment statement L-Value must be a container ( i.e. which have ability to hold the data)
3. Variable is the only container in C thus L Value must be any Variable.
4. L Value Cannot be Constant,Function or any of the available data type in C

Diagram Showing Lvalue :

Example of LValue :

#include<stdio.h>
int main()
{
int num;
num = 5;
return(0);
}

In the above expression, Constant value 5 is being assigned to a variable ‘num’. Variable ‘num’ is called as storage region’s , ‘num’ can considered as LValue of an expression.

Important Concepts about : LValue of an Expression

Tip 1 : Lvalue cannot be a Constant

int main()
{
int num;
5 = num;  //Error
return(0);
}

Tip 2 : Lvalue cannot be a Constant Variable

int main()
{
const num;
num = 20;  //Error
return(0);
}

Tip 3 : Lvalue cannot be a MACRO

#define MAX 20
int main()
{
MAX = 20;  //Error
return(0);
}

Tip 4 : Lvalue cannot be a Enum Constant

enum {JAN,FEB,MARCH};
int main()
{
JAN = 20;  //Error
return(0);
}

Tip 5 : Lvalue cannot be a Data Type

#define<stdio.h>
#define max 125
struct book{
  char *name;
  int  pages;
};
void main()
{
book = {"C Programming",100};
}

How to solve this error : L-Value Require error ?

Causes of Error :

1. Whenever we are trying to assign value to constant value
2. Whenever we are trying to increment or decrement Constant Expression
3. Inside if statement , if we try to write comparison operator as “= =” instead of ”==”, then we will get this error.

Solution :

Solution to this problem is very simple -