Gangmax Blog

C++ Code Snippets

From here.

test.cpp
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#include <iostream>

int main()
{
using namespace std;
cout << "Hello, world!" << endl;
return 0;
}
sys.cpp
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#include <iostream>
#include <stdlib.h>
using namespace std;
int main()
{
system("echo -n '\nHostname: '"); system("hostname");
system("echo -n '\nIP Address: '"); system("ip a");
system("echo -n '\nDate/Time: '"); system("date");
system("echo '\nFilesystem Utilization:'"); system("df -h; echo");
return 0;
}
fork.cpp
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#include <iostream>
#include <unistd.h>
using namespace std;
int main()
{
pid_t PID,CPID;
PID = getpid();
CPID = fork();
if(CPID<0)
{ cout << "Error starting child process\n";
return 1;
}
else
{
cout << "The PID of the current process: " << PID << endl;
cout << "The PID of the new child process: " << CPID << endl;
}
return 0;
}
pid.cpp
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#include <iostream>
#include <unistd.h>
using namespace std;
int main()
{
pid_t PID,CPID;
PID = getpid();
CPID = fork();
if(CPID<0)
{ cout << "Error starting child process\n";
return 1;
}
else
{
cout << "The PID of the current process: " << PID << endl;
cout << "The PID of the new child process: " << CPID << endl;
}
return 0;
}
pointer.cpp
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#include <iostream>
#include <unistd.h>
using namespace std;
int main()
{
int myAge = 40;

int* agePtr = &myAge;

cout << "Address of pointer is pointing " << agePtr << endl;

cout << "Address of pointer " << &agePtr << endl;
cout << "Data at memory address " << *agePtr << endl;


int** agePtrPtr = &agePtr;

cout << "agePtr " << *agePtrPtr << endl;

cout << "Data " << **agePtrPtr << endl;

int* nullPtr = 0;

cout << "Data " << *nullPtr << endl;

return 0;
}

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