[user02@FC4 Lesson04]$ cat -n setw.c

   1  #include <stdio.h>
   2
   3  int main(void)
   4  {
   5    printf("My favorite number is%3d\n", 1001);
   6    printf("My favorite number is%4d\n", 1001);
   7    printf("My favorite number is%5d\n", 1001);
   8    printf("My favorite number is%6d\n", 1001);
   9
  10    return 0;
  11  }

[user02@FC4 Lesson04]$ gcc -o setw setw.c
[user02@FC4 Lesson04]$ ./setw
My favorite number is1001
My favorite number is1001
My favorite number is 1001
My favorite number is 1001
[user02@FC4 Lesson04]$