#include <iostream>
using namespace std;
int main() {
cout << "Size of int is " << sizeof(int) << "byte" << endl;
cout << "Size of short is " << sizeof(short) << "byte" << endl;
cout << "Size of long is " << sizeof(long) << "byte" << endl;
cout << "Size of float is " << sizeof(float) << "byte" << endl;
cout << "Size of double is " << sizeof(double)<< "byte" << endl;
cout << "Size of char is " << sizeof(char) << "byte" << endl;
cout << "Size of bool is " << sizeof(bool) << "byte" << endl;
system("pause");
return 0;
}
將檔案存成size.cpp並執行下列的指令bcc32 size.cpp
Size of int is 4byte Size of short is 2byte Size of long is 4byte Size of float is 4byte Size of double is 8byte Size of char is 1byte Size of bool is 1byte這邊說明一下程式的內容
# vim main.c
#include <stdio.h>
int main()
{
printf("Hello world!!!\n");
return 0;
}
# gcc main.c -o test
這時我們會有一個test的執行檔# file test test: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, not stripped可以從上面的描述得知
# ldd test
linux-gate.so.1 => (0x00614000)
libc.so.6 => /lib/libc.so.6 (0x00697000)
/lib/ld-linux.so.2 (0x00676000)
可以知道有用到兩個函式庫 :# gcc -static main.c -o test_static這時test_static的檔案大小就會飆升到632124
# file test_static test_static: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.32, not stripped這個檔案就無法使用ldd的指令了
#include <iostream>
using std::cout;
using std::endl;
int main()
{
cout << "Hello World, C++" << endl;
return 0;
}
將檔案存成helloworld.cpp# bcc32 helloworld.cpp
接著會多出一個helloworld.exe的執行檔"Hello World, C++"
#include <iostream>
using std::cout; using std::endl;是指說本程式會用到"std這個名稱空間"裡的cout與endl的標準函式。為什麼要這樣定義呢?因為很有可能大家都會定義到相同的函式名稱，所以指定好特定的名稱空間，這樣就不會搞錯了。
int main()
{
cout << "Hello World, C++" << endl;
return 0;
}
int是只要傳出的資料型態，int是整數的資料型態。main是所有程式一開始的執行的位置。
# yum install postfix # yum remove sendmail # vim /etc/postfix/main.cf myhostname = guider.com myorigin = $myhostname inet_interfaces = all inet_protocaols = all # /etc/init.d/postfix start # netstat -tlunp |grep :25
# vim /etc/hosts 3ffe:1:2::1 ipv6.server # vim /tmp/test testing ipv6 EOF # mailx -S verbose -S from=eki-1322 -S smtp=ipv6.server –s mailtest test@test.com < /tmp/test
# postqueue –p
# yum install tftp-server # vim /etc/xinet.d/tftp disable = no flag = IPv6 # /sbin/chkconfig tftp on # /sbin/chkconfig xinetd on # /sbin/service xinetd start
# tftp 3ffe:1:2::1
# yum install ntp # vim /etc/ntp.conf restrict -6 default kod nomodify notrap nopeer noquery restrict -6 ::1 restrict -6 fe80::0 mask 64 nomodify restrict -6 3ffe:1:2::0 mask 64 server 127.127.1.0 fudge 127.127.1.0 stratum 8 # /etc/init.d/ntpd start # chkconfig ntpd on # netstat –tlunp |grep ntp
# date 12121212 # date # ntpdate 3ffe:1:2::1 # date
# yum install net-snmp net-snmp-utils
# snmpget -v 1 -c public udp6:[3ffe:1:2::1]:161 1.3.6.1.2.1.1.3.0 # snmpwalk -v 1 -c public udp6:[3ffe:1:2::1]:161 1.3.6.1.2.1.1
http://[3ffe:1:2::2]
https://[3ffe:1:2::2]
# yum install telnet-server # chkconfig telnet on
# telnet 3ffe:1:2::1