Code

 Header...
//
// Demonstrate problem trying to modify a fixed string
//
void myfunction (char message[]);

 void myfunction(char message[]){
   ... 

»  printf("The original message was: %s\n", message);

»  message0='A';
»  printf("The new message is: %s\n", message);
}

 int main(){
   ... 

»  myfunction("Hello, world");// Subtle error!
»  return 0;
}

// This program failed to complete properly
// See if you can work out why by
// stepping throught the code.