#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */

/* Variables and functions */
int /*<<< orphan*/ printf(char *);
int /*<<< orphan*/ scanf(char *, char *);
int main(void) {
  char c;
  printf("Enter a single character: ");
  scanf("%c", &c);
  if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) {
    printf("It's an alphabetic character.\n");
  } else if (c >= '0' && c <= '9') {
    printf("it's a digit.\n");
  } else {
    printf("It's a special character.\n");
  }
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeca(%rip),%rdi
call   1030 <printf@plt>
lea    0xed9(%rip),%rdi
lea    -0x5(%rbp),%rsi
call   1040 <scanf@plt>
movsbl -0x5(%rbp),%eax
cmp    $0x61,%eax
jl     1165 <main+0x45>
movsbl -0x5(%rbp),%eax
cmp    $0x7a,%eax
jle    117f <main+0x5f>
movsbl -0x5(%rbp),%eax
cmp    $0x41,%eax
jl     1190 <main+0x70>
movsbl -0x5(%rbp),%eax
cmp    $0x5a,%eax
jg     1190 <main+0x70>
lea    0xe98(%rip),%rdi
call   1030 <printf@plt>
jmp    11cc <main+0xac>
movsbl -0x5(%rbp),%eax
cmp    $0x30,%eax
jl     11bb <main+0x9b>
movsbl -0x5(%rbp),%eax
cmp    $0x39,%eax
jg     11bb <main+0x9b>
lea    0xe8c(%rip),%rdi
call   1030 <printf@plt>
jmp    11c7 <main+0xa7>
lea    0xe8a(%rip),%rdi
call   1030 <printf@plt>
jmp    11cc <main+0xac>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rax
lea    0xec8(%rip),%rdi
call   1040 <printf@plt>
lea    0xed7(%rip),%rdi
lea    0x7(%rsp),%rsi
call   1050 <scanf@plt>
mov    0x7(%rsp),%al
mov    %eax,%ecx
and    $0xdf,%cl
add    $0xbf,%cl
add    $0xd0,%al
cmp    $0xa,%al
lea    0xed3(%rip),%rax
lea    0xeb2(%rip),%rdx
cmovb  %rax,%rdx
cmp    $0x1a,%cl
lea    0xecc(%rip),%rdi
cmovae %rdx,%rdi
call   1030 <puts@plt>
xor    %eax,%eax
pop    %rcx
ret

LLVM IR (-O0):
@.str = [27 x i8] c"Enter a single character: \00"
@.str.1 = [3 x i8] c"%c\00"
@.str.2 = [31 x i8] c"It's an alphabetic character.\0A\00"
@.str.3 = [15 x i8] c"it's a digit.\0A\00"
@.str.4 = [27 x i8] c"It's a special character.\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i8
store i32 0, i32* %1
%3 = call i32 @printf(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str, i64 0, i64 0))
%4 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %2)
%5 = load i8, i8* %2
%6 = sext i8 %5 to i32
%7 = icmp sge i32 %6, 97
br i1 %7, label %8, label %12
8: ; preds = %0
%9 = load i8, i8* %2
%10 = sext i8 %9 to i32
%11 = icmp sle i32 %10, 122
br i1 %11, label %20, label %12
12: ; preds = %8, %0
%13 = load i8, i8* %2
%14 = sext i8 %13 to i32
%15 = icmp sge i32 %14, 65
br i1 %15, label %16, label %22
16: ; preds = %12
%17 = load i8, i8* %2
%18 = sext i8 %17 to i32
%19 = icmp sle i32 %18, 90
br i1 %19, label %20, label %22
20: ; preds = %16, %8
%21 = call i32 @printf(i8* getelementptr inbounds ([31 x i8], [31 x i8]* @.str.2, i64 0, i64 0))
br label %35
22: ; preds = %16, %12
%23 = load i8, i8* %2
%24 = sext i8 %23 to i32
%25 = icmp sge i32 %24, 48
br i1 %25, label %26, label %32
26: ; preds = %22
%27 = load i8, i8* %2
%28 = sext i8 %27 to i32
%29 = icmp sle i32 %28, 57
br i1 %29, label %30, label %32
30: ; preds = %26
%31 = call i32 @printf(i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.3, i64 0, i64 0))
br label %34
32: ; preds = %26, %22
%33 = call i32 @printf(i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str.4, i64 0, i64 0))
br label %34
34: ; preds = %32, %30
br label %35
35: ; preds = %34, %20
ret i32 0
}

LLVM IR (-O2):
@.str = [27 x i8] c"Enter a single character: \00"
@.str.1 = [3 x i8] c"%c\00"
@str = [26 x i8] c"It's a special character.\00"
@str.5 = [14 x i8] c"it's a digit.\00"
@str.6 = [30 x i8] c"It's an alphabetic character.\00"
define i32 @main() {
%1 = alloca i8
%2 = tail call i32 @printf(i8* dereferenceable(1) getelementptr inbounds ([27 x i8], [27 x i8]* @.str, i64 0, i64 0))
%3 = call i32 @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0), i8* %1)
%4 = load i8, i8* %1
%5 = and i8 %4, -33
%6 = add i8 %5, -65
%7 = icmp ult i8 %6, 26
%8 = add i8 %4, -48
%9 = icmp ult i8 %8, 10
%10 = select i1 %9, i8* getelementptr inbounds ([14 x i8], [14 x i8]* @str.5, i64 0, i64 0), i8* getelementptr inbounds ([26 x i8], [26 x i8]* @str, i64 0, i64 0)
%11 = select i1 %7, i8* getelementptr inbounds ([30 x i8], [30 x i8]* @str.6, i64 0, i64 0), i8* %10
%12 = call i32 @puts(i8* dereferenceable(1) %11)
ret i32 0
}