C programming Interview questions and answers: Value of variable in c language

Explanation of value of a variable in c programming language by examples and questions and answers

Data which any variable keeps is known as value of variable. For example:

int a=5;

Here value of variable a is five. Name of variable always returns value of the variable.

How to assign any value to a variable:

C supports eleven type of assignment operator to assign any value to operator. Those are:

(a) =

(b) +=

(d) v*=

(e) /=

(f) %=

(g) <<=

(h) >>=

(i) |=

(j) &=

(k) ^=

In this chapter will discuss only first operator i.e. =

Assignment statement in c:

LValue: Lvalue stands for left value. In any assignment statement LValue must be a container i.e. which have ability to hold the data. In c has only one type only container and which is variable. Hence LValue must be any variable in c it cannot be a constant, function or any other data type of c. For example

#define <stdio.h>

#define max 125

struct abc{

char *name;

int roll;

};

enum {RED,BLUE};

int main(){

int a;

const b;

a=5;

//10=5; LValue cannot be a integer constant

//max=20; //Lvalue cannot be a micro constant

//b=11; Lvalue cannot be a constant variable

//float=3.3f; Lvalue cannot be a data type

//abc={“sachin”,5}; Lvalue cannot be a data type

//BLUE =2; Lvalue cannot be a enum constant

return 0;

}

RValue: In any assignment statement RValue must be anything which can return and constant value or it is itself a constant. RValue can be any c constants, variables, function which is returning a value etc. For example:

#include<stdio.h>

#define max 5

void display();

float sum();

enum {BLACK, WHITE};

int main(){

int x=2; //RValue can be a constant.

float y=9.0;

const int z=x; //RValue can be a constant variable

x=max; //RValue can be a variable.

x=BLACK; //RValue can be a enum constant.

y=sum();//RValue can be a function.