#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 *, ...);
int strncmp(char *, char *, int);
int main() {
  char s1[20], s2[20];
  int cmp;
  int num;
  printf("Please input the first string:");
  scanf("%20s", s1);
  printf("Please input the second string:");
  scanf("%20s", s2);
  printf("Please input the compare number:");
  scanf("%d", &num);
  cmp = strncmp(s1, s2, num);
  printf("%d\n", cmp);
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x50,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xeba(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    -0x20(%rbp),%rsi
lea    0xec7(%rip),%rdi
mov    $0x0,%al
call   1050 <scanf@plt>
lea    0xebe(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    -0x40(%rbp),%rsi
lea    0xea7(%rip),%rdi
mov    $0x0,%al
call   1050 <scanf@plt>
lea    0xebe(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xed1(%rip),%rdi
lea    -0x48(%rbp),%rsi
mov    $0x0,%al
call   1050 <scanf@plt>
lea    -0x20(%rbp),%rdi
lea    -0x40(%rbp),%rsi
mov    -0x48(%rbp),%edx
call   1030 <strncmp@plt>
mov    %eax,-0x44(%rbp)
mov    -0x44(%rbp),%esi
lea    0xeac(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x50,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r15
push   %r14
push   %rbx
sub    $0x50,%rsp
lea    0xec0(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xed1(%rip),%rbx
lea    0x30(%rsp),%r14
mov    %rbx,%rdi
mov    %r14,%rsi
xor    %eax,%eax
call   1050 <scanf@plt>
lea    0xebd(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0x10(%rsp),%r15
mov    %rbx,%rdi
mov    %r15,%rsi
xor    %eax,%eax
call   1050 <scanf@plt>
lea    0xebd(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xed0(%rip),%rdi
lea    0xc(%rsp),%rsi
xor    %eax,%eax
call   1050 <scanf@plt>
mov    0xc(%rsp),%edx
mov    %r14,%rdi
mov    %r15,%rsi
call   1030 <strncmp@plt>
lea    0xeb1(%rip),%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
add    $0x50,%rsp
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
@.str = [31 x i8] c"Please input the first string:\00"
@.str.1 = [5 x i8] c"%20s\00"
@.str.2 = [32 x i8] c"Please input the second string:\00"
@.str.3 = [33 x i8] c"Please input the compare number:\00"
@.str.4 = [3 x i8] c"%d\00"
@.str.5 = [4 x i8] c"%d\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca [20 x i8]
%3 = alloca [20 x i8]
%4 = alloca i32
%5 = alloca i32
store i32 0, i32* %1
%6 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([31 x i8], [31 x i8]* @.str, i64 0, i64 0))
%7 = getelementptr inbounds [20 x i8], [20 x i8]* %2, i64 0, i64 0
%8 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8* %7)
%9 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @.str.2, i64 0, i64 0))
%10 = getelementptr inbounds [20 x i8], [20 x i8]* %3, i64 0, i64 0
%11 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8* %10)
%12 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([33 x i8], [33 x i8]* @.str.3, i64 0, i64 0))
%13 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.4, i64 0, i64 0), i32* %5)
%14 = getelementptr inbounds [20 x i8], [20 x i8]* %2, i64 0, i64 0
%15 = getelementptr inbounds [20 x i8], [20 x i8]* %3, i64 0, i64 0
%16 = load i32, i32* %5
%17 = call i32 @strncmp(i8* %14, i8* %15, i32 %16)
store i32 %17, i32* %4
%18 = load i32, i32* %4
%19 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.5, i64 0, i64 0), i32 %18)
ret i32 0
}

LLVM IR (-O2):
@.str = [31 x i8] c"Please input the first string:\00"
@.str.1 = [5 x i8] c"%20s\00"
@.str.2 = [32 x i8] c"Please input the second string:\00"
@.str.3 = [33 x i8] c"Please input the compare number:\00"
@.str.4 = [3 x i8] c"%d\00"
@.str.5 = [4 x i8] c"%d\0A\00"
define i32 @main() {
%1 = alloca [20 x i8]
%2 = alloca [20 x i8]
%3 = alloca i32
%4 = getelementptr inbounds [20 x i8], [20 x i8]* %1, i64 0, i64 0
%5 = getelementptr inbounds [20 x i8], [20 x i8]* %2, i64 0, i64 0
%6 = bitcast i32* %3 to i8*
%7 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([31 x i8], [31 x i8]* @.str, i64 0, i64 0))
%8 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8* %4)
%9 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([32 x i8], [32 x i8]* @.str.2, i64 0, i64 0))
%10 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8* %5)
%11 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([33 x i8], [33 x i8]* @.str.3, i64 0, i64 0))
%12 = call i32 (i8*, ...) @scanf(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.4, i64 0, i64 0), i32* %3)
%13 = load i32, i32* %3
%14 = call i32 @strncmp(i8* %4, i8* %5, i32 %13)
%15 = call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([4 x i8], [4 x i8]* @.str.5, i64 0, i64 0), i32 %14)
ret i32 0
}