Uninitialized variable problem

GCC Provides some pretty good warning features for you, to help avoid common problems.
One of this is warning for uninitialzed variables.

Let's see the following code:

 typedef union  
 {  
   uint8_t value1;  
   uint8_t value2;  
 } demostruct;  
 .  
 .  
 .  
 demostruct uninited;  
 int i;  
 for (i = 0; i < uninited.value1; i++)  
 {  
      //do something  
 }  

You'll probably be in some serious trouble running this code, as whatever you do in the for loop, the execution of it surely won't be as you imagined.