Variables in c

Variable

When we want to store any information . we store it in address of the computer address  is complex so we name it and naming of address known as variable.
  
Variable declaration :- data_type variable_name;
                                     Example: int x, y, z; char name;


Variable initialization :- data_type variable_name = value;

                                       Example: int x = 50, y = 30;


There are Two types of Variables in c language.

• Local Variable.
• Global Variable.

     Local Variable

• The scope of local variables will be within the function only.
• These variables are declared within the function and can’t be accessed outside the function.
• In the below example, m and n variables are having scope within the main function only. These are not visible to test function.
• Like wise, a and b variables are having scope within the test function only. These are not visible to main function. 

 For Example:-

#include<stdio.h>

void test();

int main()

{

   int a = 20, b = 40;

        // a,b are local variables of main function

        //a and b variables are having scope

        within this main function only.

       

   printf("values : a = %d and  b = %d", a, b);

   test();

}

void test()

{

   int x= 30, y = 50;

        // x, y are local variables of test function

        /x and y variables are having scope

        within this test function only.

       

   printf("values : x = %d and y = %d", x, y);

} 

Output:-

values : a = 20 and b = 40

values : x = 30 and y = 50

Global Variable

• The scope of global variables will be throughout the program. These variables can be accessed from anywhere in the program.
• This variable is defined outside the main function. So that, this variable is visible to main function and all other sub functions.

For Example:-

#include<stdio.h>
 Void test();
int a = 20 , b = 40;
int x = 30 , y = 50;

int main()
{
   printf("all variables are accessed from main function");
   printf("values : a=%d:b=%d:x=%d:y=%d",a,b,x,y);
   test();
}
   void test()
{
   printf("all variables are accessed from test function")
   printf("values: a=%d:b=%d:x=%d:y=%d",a,b,x,y);
}

Output:-    All variables are accessed from main function
                 values : a= 20 : b = 40 : x = 30 : y = 50
                 All variables are accessed from test function
                 values : a= 20 : b = 40 : x = 30 : y = 50