User-Defined Functions

Write a multifunction to illustrate how automatic variables work.
A program with two subprograms function1 and function2 is shown m is an automatic variable and it is declared at the beginning of each function. m is initialized to 10,100, and 1000 in function1, function2 and main respectively. When executed, main calls function2 which in turn calls function1. When main is active, m = 1000; but when function2 is called, the main's m is temporarily put on the shelf and the new local m = 100 becomes active. Similarly, when function1 is called, both the previous values of m are put on the shelf and the latest value of (m=10) becomes active. As soon as function1 (m=10) is finished, function2 (m=100) takes over again. As soon it is done, main (m=1000) takes over. The output clearly shows that the value assigned to m in one function does not affect its value in the other functions; and the local value of m is destroyed when it leaves a function.

#include <stdio.h>
void function1(void);
void function2(void);
void main( )
   {
 int m = 1000;
 function2();
 printf("%d\n",m); /* Third output */
 getch();
   }
   void function1(void)
   {
 int m = 10;
 printf("%d\n",m); /* First output */
   }
                                                        
   void function2(void)                                                
   {                                                          
        int m = 100;                                          
        function1();                                          
        printf("%d\n",m); /* Second output */                                     
   }

OUTPUT
10
100
1000