Let's consider this C code:

```
#include <stdio.h>

main()
{
  int x=5;
  printf("x is ");
  printf("%d",5);
}

```

In this, when we wrote `int x=5;` we told the computer that `x` is an integer. The computer must remember that `x` is an integer. But when we output the value of `x` in `printf()` we have to again tell the computer that `x` is an integer. Why is that? 

Why does the computer forget that `x` was an integer?