Beispielprogramme 16.4.2018

20180416/ad-20180416.tex

@@ -26,6 +26,7 @@
 
 \usepackage{pgslides}
 \usepackage{tikz}
+\usepackage{soul}
 
 \newcommand{\underconstruction}{%
   \begin{picture}(0,0)
@@ -333,8 +334,9 @@
     \pause
     \item
       Ab C++11: \lstinline{constexpr}-Funktionen\\%\pause\\
+      {\color{red}\dots\ anscheinend auch ohne "`constexpr"' \dots}\\
       darf nur aus einem einzigen \lstinline{return}-Statement bestehen\\
-      \textarrow\ keine Schleife, aber Rekursion erlaubt
+      \textarrow\ keine Schleife {-- \color{red}\strikeout{oder vielleicht doch} außer ab C++14 --}, aber Rekursion erlaubt
     \pause
     \item
       leere Parameterliste: \lstinline{void} optional\\

20180416/const-1.c

+#include <stdio.h>
+
+#define ANSWER 42
+
+int main (void)
+{
+  printf ("%d\n", ANSWER);
+  return 0;
+}

20180416/const-10.c

+#include <stdio.h>
+
+constexpr long long unsigned fak (int n)
+{
+  long long unsigned result = 1;
+  for (int i = 2; i < n; i++)
+    result *= i;
+  return result;
+}
+
+const long long unsigned fak10 = fak (10);
+
+int large_array[fak10];
+
+int main (void)
+{
+  printf ("%llu\n", fak10);
+  printf ("%d\n", large_array[1117]);
+  return 0;
+}

20180416/const-11.c

+#include <stdio.h>
+
+constexpr long long unsigned fak (int n)
+{
+  if (n < 2)
+    return 1;
+  else
+    return n * fak (n - 1);
+}
+
+const long long unsigned fak10 = fak (10);
+
+int large_array[fak10];
+
+int main (void)
+{
+  printf ("%llu\n", fak10);
+  printf ("%d\n", large_array[1117]);
+  return 0;
+}

20180416/const-12.c

+#include <stdio.h>
+
+constexpr long long unsigned fak (int n)
+{
+  return n < 2 ? 1 : n * fak (n - 1);
+}
+
+const long long unsigned fak10 = fak (10);
+
+int large_array[fak10];
+
+int main (void)
+{
+  printf ("%llu\n", fak10);
+  printf ("%d\n", large_array[1117]);
+  return 0;
+}

20180416/const-2.c

+#include <stdio.h>
+
+const int answer = 42;
+
+int main (void)
+{
+  printf ("%d\n", answer);
+  return 0;
+}

20180416/const-3.c

+#include <stdio.h>
+
+#define n 5
+
+int prime[n] = { 2, 3, 5, 7, 11 };
+
+int main (void)
+{
+  for (int i = 0; i < n; i++)
+    printf ("%d\n", prime[i]);
+  return 0;
+}

20180416/const-4.c

+#include <stdio.h>
+
+const int n = 5;
+
+int prime[n] = { 2, 3, 5, 7, 11 };
+
+int main (void)
+{
+  for (int i = 0; i < n; i++)
+    printf ("%d\n", prime[i]);
+  return 0;
+}

20180416/const-5.c

+#include <stdio.h>
+
+const int n = 5;
+
+int prime[5] = { 2, 3, 5, 7, 11 };
+
+int main (void)
+{
+  n = 42;
+  for (int i = 0; i < n; i++)
+    printf ("%d\n", prime[i]);
+  return 0;
+}

20180416/const-6.c

+#include <stdio.h>
+
+const int n = 5;
+
+int prime[n] = { 2, 3, 5, 7, 11 };
+
+int main (void)
+{
+  printf ("%016x\n", (long long unsigned) &n);
+  return 0;
+}

20180416/const-7.c

+#include <stdio.h>
+
+int square (int x)
+{
+  return x * x;
+}
+
+const int vier = square (2);
+
+int main (void)
+{
+  printf ("%d\n", vier);
+  return 0;
+}

20180416/const-8.c

+#include <stdio.h>
+
+constexpr int square (int x)
+{
+  return x * x;
+}
+
+const int vier = square (2);
+
+int main (void)
+{
+  printf ("%d\n", vier);
+  return 0;
+}

20180416/const-9.c

+#include <stdio.h>
+
+constexpr long long unsigned fak (int n)
+{
+  long long unsigned result = 1;
+  for (int i = 2; i < n; i++)
+    result *= i;
+  return result;
+}
+
+const long long unsigned fak10 = fak (10);
+
+int main (void)
+{
+  printf ("%llu\n", fak10);
+  return 0;
+}

20180416/functions-1.cpp

+#include <stdio.h>
+
+void print (char *s)
+{
+  printf ("%s", s);
+}
+
+void print (int i)
+{
+  printf ("%d", i);
+}
+
+void print ()
+{
+  printf ("\n");
+}
+
+int main ()
+{
+  print ("The answer is: ");
+  print (42);
+  print ();
+  return 0;
+}

20180416/functions-2.cpp

+#include <stdio.h>
+
+void print (const char *s)
+{
+  printf ("%s", s);
+}
+
+void print (int i)
+{
+  printf ("%d", i);
+}
+
+void print ()
+{
+  printf ("\n");
+}
+
+int main ()
+{
+  print ("The answer is: ");
+  print (42);
+  print ();
+  return 0;
+}

20180416/functions-2.s

+	.file	"functions-2.cpp"
+	.section	.rodata.str1.1,"aMS",@progbits,1
+.LC0:
+	.string	"%s"
+	.text
+	.globl	_Z5printPKc
+	.type	_Z5printPKc, @function
+_Z5printPKc:
+.LFB12:
+	.cfi_startproc
+	subq	$8, %rsp
+	.cfi_def_cfa_offset 16
+	movq	%rdi, %rsi
+	leaq	.LC0(%rip), %rdi
+	movl	$0, %eax
+	call	printf@PLT
+	addq	$8, %rsp
+	.cfi_def_cfa_offset 8
+	ret
+	.cfi_endproc
+.LFE12:
+	.size	_Z5printPKc, .-_Z5printPKc
+	.section	.rodata.str1.1
+.LC1:
+	.string	"%d"
+	.text
+	.globl	_Z5printi
+	.type	_Z5printi, @function
+_Z5printi:
+.LFB13:
+	.cfi_startproc
+	subq	$8, %rsp
+	.cfi_def_cfa_offset 16
+	movl	%edi, %esi
+	leaq	.LC1(%rip), %rdi
+	movl	$0, %eax
+	call	printf@PLT
+	addq	$8, %rsp
+	.cfi_def_cfa_offset 8
+	ret
+	.cfi_endproc
+.LFE13:
+	.size	_Z5printi, .-_Z5printi
+	.globl	_Z5printv
+	.type	_Z5printv, @function
+_Z5printv:
+.LFB14:
+	.cfi_startproc
+	subq	$8, %rsp
+	.cfi_def_cfa_offset 16
+	movl	$10, %edi
+	call	putchar@PLT
+	addq	$8, %rsp
+	.cfi_def_cfa_offset 8
+	ret
+	.cfi_endproc
+.LFE14:
+	.size	_Z5printv, .-_Z5printv
+	.section	.rodata.str1.1
+.LC2:
+	.string	"The answer is: "
+	.text
+	.globl	main
+	.type	main, @function
+main:
+.LFB15:
+	.cfi_startproc
+	subq	$8, %rsp
+	.cfi_def_cfa_offset 16
+	leaq	.LC2(%rip), %rdi
+	call	_Z5printPKc
+	movl	$42, %edi
+	call	_Z5printi
+	call	_Z5printv
+	movl	$0, %eax
+	addq	$8, %rsp
+	.cfi_def_cfa_offset 8
+	ret
+	.cfi_endproc
+.LFE15:
+	.size	main, .-main
+	.ident	"GCC: (Debian 6.3.0-18) 6.3.0 20170516"
+	.section	.note.GNU-stack,"",@progbits

20180416/functions-3.cpp

+#include <stdio.h>
+
+extern void print (const char *s);
+
+void print (int i)
+{
+  printf ("%d", i);
+}
+
+void print ()
+{
+  printf ("\n");
+}
+
+int main ()
+{
+  print ("The answer is: ");
+  print (42);
+  print ();
+  return 0;
+}

20180416/functions-3l.c

+#include <stdio.h>
+
+void print (const char *s)
+{
+  printf ("%s", s);
+}

20180416/functions-4.cpp

+#include <stdio.h>
+
+extern void print (const char *s);
+
+void print (int i)
+{
+  printf ("%d", i);
+}
+
+void print ()
+{
+  printf ("\n");
+}
+
+int main ()
+{
+  print ("The answer is: ");
+  print (42);
+  print ();
+  return 0;
+}