user: Demonstrate the C code that generates the assembly output below:

```asm
<Getop>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x20,%rsp
  mov    %rdi,-0x18(%rbp)
  movl   $0x0,-0xc(%rbp)
  nop
L86:
  mov    $0x0,%eax
  call   <getch@plt>
  mov    %eax,-0x8(%rbp)
  mov    -0x8(%rbp),%eax
  mov    %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    %dl,(%rax)
  mov    -0x18(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x20,%al
  je     L86
  cmpl   $0x9,-0x8(%rbp)
  je     L86
  mov    -0x18(%rbp),%rax
  add    $0x1,%rax
  movb   $0x0,(%rax)
  mov    -0x8(%rbp),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isalpha@plt>
  test   %rax,%rax
  je     L192
  movl   $0x0,-0xc(%rbp)
  jmp    L170
L53:
  mov    $0x0,%eax
  call   <getch@plt>
  mov    %eax,-0x8(%rbp)
L170:
  mov    -0xc(%rbp),%eax
  lea    0x1(%rax),%edx
  mov    %edx,-0xc(%rbp)
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    -0x8(%rbp),%edx
  mov    %dl,(%rax)
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isalpha@plt>
  test   %rax,%rax
  jne    L53
  mov    -0xc(%rbp),%eax
  cltq
  lea    -0x1(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  mov    D14(%rip),%rax
  mov    (%rax),%eax
  cmp    %eax,-0x8(%rbp)
  je     L71
  mov    -0x8(%rbp),%eax
  mov    %eax,%edi
  call   <unGetch@plt>
L71:
  mov    $0x1,%eax
  jmp    L150
L192:
  mov    -0x8(%rbp),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L70
  cmpl   $0x2e,-0x8(%rbp)
  je     L70
  cmpl   $0x2d,-0x8(%rbp)
  je     L70
  cmpl   $0x3d,-0x8(%rbp)
  jne    L221
  mov    $0x0,%eax
  call   <getch@plt>
  mov    %eax,-0x4(%rbp)
  cmpl   $0xa,-0x4(%rbp)
  jne    L221
  mov    $0x0,%edi
  call   <unGetch@plt>
  mov    -0x8(%rbp),%eax
  jmp    L150
L221:
  cmpl   $0x0,-0x8(%rbp)
  jne    L17
  mov    $0x2,%eax
  jmp    L150
L17:
  mov    -0x8(%rbp),%eax
  jmp    L150
L70:
  cmpl   $0x2d,-0x8(%rbp)
  jne    L228
  mov    $0x0,%eax
  call   <getch@plt>
  mov    %eax,-0x4(%rbp)
  mov    -0x4(%rbp),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L148
  cmpl   $0x2e,-0x4(%rbp)
  je     L148
  mov    -0x8(%rbp),%eax
  jmp    L150
L148:
  mov    -0x4(%rbp),%eax
  mov    %eax,-0x8(%rbp)
  jmp    L235
L228:
  mov    $0x0,%eax
  call   <getch@plt>
  mov    %eax,-0x8(%rbp)
  jmp    L235
L51:
  mov    $0x0,%eax
  call   <getch@plt>
  mov    %eax,-0x8(%rbp)
L235:
  addl   $0x1,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    -0x8(%rbp),%edx
  mov    %dl,(%rax)
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L51
  cmpl   $0x2e,-0x8(%rbp)
  jne    L250
  nop
L190:
  mov    $0x0,%eax
  call   <getch@plt>
  mov    %eax,-0x8(%rbp)
  addl   $0x1,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    -0x8(%rbp),%edx
  mov    %dl,(%rax)
  movzbl (%rax),%eax
  movsbl %al,%eax
  mov    %eax,%edi
  call   <isdigit@plt>
  test   %rax,%rax
  jne    L190
L250:
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  mov    D14(%rip),%rax
  mov    (%rax),%eax
  cmp    %eax,-0x8(%rbp)
  je     L60
  mov    -0x8(%rbp),%eax
  mov    %eax,%edi
  call   <unGetch@plt>
L60:
  mov    $0x0,%eax
L150:
  leave
  ret
```

assistant: ```c
int Getop(char s[]) {
  int i = 0;
  int c;
  int next;
  while ((s[0] = c = getch()) == ' ' || c == '\t') {
    ;
  }
  s[1] = '\0';
  if (isalpha(c)) {
    i = 0;
    while (isalpha(s[i++] = c)) {
      c = getch();
    }
    s[i - 1] = '\0';
    if (c != EOF)
      unGetch(c);
    return 1;
  }
  if (!isdigit(c) && c != '.' && c != '-') {
    if ('=' == c && '\n' == (next = getch())) {
      unGetch('\0');
      return c;
    }
    if ('\0' == c)
      return 2;
    return c;
  }
  if (c == '-') {
    next = getch();
    if (!isdigit(next) && next != '.') {
      return c;
    }
    c = next;
  } else {
    c = getch();
  }
  while (isdigit(s[++i] = c)) {
    c = getch();
  }
  if (c == '.') {
    while (isdigit(s[++i] = c = getch()))
      ;
  }
  s[i] = '\0';
  if (c != EOF)
    unGetch(c);
  return 0;
}
```