Puzzle SL3

Rule 4

What does the following code write to the monitor?

#include <stdio.h>
int main( void )
{
  int a = 1;
  int b = 2;
  
  printf("main   : a=%d\tb=%d\n", a, b );
  
  {
    int b = 3;
    printf("block1 : a=%d\tb=%d\n", a, b );
  }
  
  {
    printf("block2s: a=%d\tb=%d\n", a, b );

    int a = 4;
    printf("block2e: a=%d\tb=%d\n", a, b );
  }
  
  printf("main   : a=%d\tb=%d\n", a, b );
  
  return 0;
}

Here, there are two sequential inner blocks, each with a declaration of a variable. All variables in this program have block scope, but different variables have scope within different blocks.