I'm having trouble displying the contents of a queue. When I pop the queue here:
for( int i = 0; i < diskQueue.size() + 1; i++ )
{
cout << left << setw(0) << "--d" << i+1 << left << setw(4) << " "
<< left << setw(14) << diskQueue.front().getFilename() << left << setw(14) << diskQueue.front().getMemoryStart()
<< left << setw(14) << diskQueue.front().getFileLength() << diskQueue.front().getRW() << endl;
diskQueue.pop();
}
I have to empty the queue, which is not what I want to do. Is there a way to print the contents of this queue without emptying it?
Here is the complete code:
#include <iostream>
#include <string>
#include <limits>
#include <queue>
#include <iomanip>
using namespace std;
/**
* Global Variables
*/
int printer;
int disk;
int cd;
int num;
string k;
int pmem, plen;
int dmem, dlen;
int cmem, clen;
string dname, pname, cname, drw, prw, crw;
/**
* Sys Gen class prompts for system information
*/
class sysGen
{
public:
void prompt() const;
};
class PCB
{
public:
PCB() : pid( 0 ), filename ( "InitialString" ), memoryLocation ( 0 ), rw ( "InitialString" ) { }
void setPid( int p );
int getPid() const;
int incrementPid();
int decrementPid();
void setFilename( string f );
string getFilename() const;
void setMemoryStart( int m );
int getMemoryStart() const;
void setFileLength( int l );
int getFileLength() const;
void setRW( string r );
string getRW() const;
void screen();
void runningPrompt() const;
queue<PCB> readyQueue;
queue<PCB> diskQueue;
queue<PCB> printerQueue;
queue<PCB> cdQueue;
private:
int pid;
string filename;
int memoryLocation;
string rw;
int fileLen;
};
void sysGen::prompt() const
{
cout << "Welcome to the Sys Gen Process"<<endl;
cout<<"Please enter the number of printers in the system (between 1 and 9)"<<endl;
while( ! ( cin >> printer ) )
{
cout << "That was not an integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
while(printer<1 || printer>9)
{
cout<<"Sorry, that is an invalid value, please re-enter amount of printers:"<<endl;
while( ! ( cin >> printer ) )
{
cout << "That was not an integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
}
cout<<"Thank you. Please enter the number of disks in the system (between 1 and 9)"<<endl;
while( ! ( cin >> disk ) )
{
cout << "That was not an integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
while(disk<1 || disk>9)
{
cout<<"Sorry, that is an invalid value, please re-enter amount of disks:"<<endl;
while( ! ( cin >> disk ) )
{
cout << "That was not an integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
}
cout<<"Please enter the number of CD/RW's in the system (between 1 and 9)"<<endl;
while( ! ( cin >> cd ) )
{
cout << "That was not an integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
while(cd<1 || cd>9)
{
cout<<"Sorry, that is an invalid value, please re-enter amount of CD/RW's:"<<endl;
while( ! ( cin >> cd ) )
{
cout << "That was not an integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
}
}
/**
* This runningPrompt Function receives input from the keyboard regarding processes
*/
void PCB::runningPrompt() const
{
cout << "You may enter a command or type 'exit' to exit the system." << endl;
PCB initialProcess;
while (k != "exit")
{
cout << "Please enter command: ";
cin >> k;
if ( k[0] == 'A' )
{
cout << "New Process created." << endl;
initialProcess.incrementPid();
cout << "Pid is " << initialProcess.getPid() << endl;
initialProcess.readyQueue.push( initialProcess );
}
if( k[0] == 't' )
{
cout << "Process terminating." << endl;
cout << "Process has entered CPU." << endl;
}
if( k[0] == 'S' )
{
initialProcess.screen();
}
if( k[1] == '1' )
num = 1;
if( k[1] == '2' )
num = 2;
if( k[1] == '3' )
num = 3;
if( k[1] == '4' )
num = 4;
if( k[1] == '5' )
num = 5;
if( k[1] == '6' )
num = 6;
if( k[1] == '7' )
num = 7;
if( k[1] == '8' )
num = 8;
if( k[1] == '9' )
num = 9;
if ( k[0] == 'd' )
{
if( !initialProcess.readyQueue.empty() )
{
cout << "This is a system call requesting Disk " << num << endl;
cout << "What is the filename? Please enter it: " << endl;
cin >> dname;
initialProcess.setFilename( dname );
cout << "What is the starting location in memory? Please enter it:" << endl;
while( ( ! ( cin >> dmem ) ) || dmem < 0 )
{
cout << "That was not a positive integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
initialProcess.setMemoryStart( dmem );
cout << "Please enter the length of your file in an integer value:" << endl;
while( ( ! ( cin >> dlen ) ) || dlen < 0 )
{
cout << "That was not positive integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
initialProcess.setFileLength( dlen );
cout << "Please enter r for read or w for write" << endl;
cin >> drw;
while( ! ( drw == "r" || drw == "w" ) )
{
cout << "Please enter a r or a w" << endl;
cin >> drw;
}
initialProcess.setRW( drw );
initialProcess.diskQueue.push( initialProcess );
initialProcess.decrementPid();
initialProcess.readyQueue.pop();
}
else
{
cout << "There are no processes in the ready queue." << endl;
}
}
if ( k[0] == 'p' )
{
cout << "This is a system call requesting printer: " << num << endl;
cout << "What is the filename? Please enter it: " << endl;
cin >> pname;
initialProcess.setFilename( pname );
cout << "What is the starting location in memory? Please enter it:" << endl;
while( ( ! ( cin >> pmem ) ) || pmem < 0 )
{
cout << "That was not a positive integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
initialProcess.setMemoryStart( pmem );
cout << "Please enter the length of your file in an integer value:" << endl;
while( ( ! ( cin >> plen ) ) || plen < 0 )
{
cout << "That was not positive integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
initialProcess.setFileLength( plen );
cout << "Please enter r for read or w for write" << endl;
cin >> prw;
while( ! ( prw == "r" || prw == "w" ) )
{
cout << "Please enter a r or a w" << endl;
cin >> prw;
}
initialProcess.setRW( prw );
initialProcess.printerQueue.push( initialProcess );
}
if ( k[0] == 'c' )
{
cout << "This is a system call requesting CD/RW: " << num << endl;
cout << "What is the filename? Please enter it: " << endl;
cin >> cname;
initialProcess.setFilename( cname );
cout << "What is the starting location in memory? Please enter it:" << endl;
while( ( ! ( cin >> cmem ) ) || cmem < 0 )
{
cout << "That was not a positive integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
initialProcess.setMemoryStart( cmem );
cout << "Please enter the length of your file in an integer value:" << endl;
while( ( ! ( cin >> clen ) ) || clen < 0 )
{
cout << "That was not positive integer...\nTry again: ";
cin.clear();
cin.ignore( numeric_limits<streamsize>::max(), '\n' );
}
initialProcess.setFileLength( clen );
cout << "Please enter r for read or w for write" << endl;
cin >> crw;
while( ! ( crw == "r" || crw == "w" ) )
{
cout << "Please enter a r or a w" << endl;
cin >> crw;
}
initialProcess.setRW( crw );
initialProcess.cdQueue.push( initialProcess );
}
if( k[0] == 'D' )
{
if( !initialProcess.diskQueue.empty() )
{
for( int i = 0; i < initialProcess.diskQueue.size(); i++ )
{
initialProcess.diskQueue.pop();
}
}
else
{
cout << "The disk queue is empty. " << endl;
}
}
}
}
void PCB::setPid(int p)
{
pid = p;
}
int PCB::getPid() const
{
return pid;
}
int PCB::incrementPid()
{
pid++;
}
void PCB::setFilename( string f )
{
filename = f;
}
string PCB::getFilename() const
{
return filename;
}
void PCB::screen()
{
cout << "Taking Snapshot." << endl;
cout << "Please select r, d, p, or c." << endl;
string rpdc;
cin >> rpdc;
while ( ! ( rpdc[0] == 'r' || rpdc[0] == 'p' || rpdc[0] == 'd' || rpdc[0] == 'c' ) )
{
cout << "Please enter r, p, d, or c. Thank you." << endl;
cout << "Enter selection" << endl;
cin >> rpdc;
}
if( rpdc[0] == 'r' )
{
cout << left << setw(9) << "PID" << left << setw(14) << "Filename"
<< left << setw(14) << "Memstart" << " R/W" << endl;
if( !readyQueue.empty() )
{
for( int i = 0; i < readyQueue.size(); i++ )
{
cout << left << setw(0) << "" << i+1 << left << setw(4) << " "
<< left << setw(14) << " " << left << setw(14) << " "
<< left << setw(14) << " " << " " << endl;
}
}
else
{
cout << left << setw(0) << "" << "0" << left << setw(4) << " "
<< left << setw(14) << " " << left << setw(14) << " "
<< left << setw(14) << " " << " " << endl;
}
}
if( rpdc[0] == 'p' )
{
cout << left << setw(9) << "PID" << left << setw(14) << "Filename"
<< left << setw(12) << "Memstart" << left << setw(14) << "FileLen" << " R/W" << endl;
if( !printerQueue.empty() )
{
for( int i = 0; i < printerQueue.size(); i++ )
{
cout << left << setw(0) << "--p" << i+1 << left << setw(4) << " "
<< left << setw(14) << printerQueue.front().getFilename() << left << setw(14) << printerQueue.front().getMemoryStart()
<< left << setw(14) << printerQueue.front().getFileLength() << printerQueue.front().getRW() << endl;
}
}
else
{
cout << left << setw(0) << "" << "0" << left << setw(4) << " "
<< left << setw(14) << " " << left << setw(14) << " "
<< left << setw(14) << " " << " " << endl;
}
}
if( rpdc[0] == 'd' )
{
cout << left << setw(9) << "PID" << left << setw(14) << "Filename"
<< left << setw(12) << "Memstart" << left << setw(14) << "FileLen" << " R/W" << endl;
if( !diskQueue.empty() )
{
for( int i = 0; i < diskQueue.size() + 1; i++ )
{
cout << left << setw(0) << "--d" << i+1 << left << setw(4) << " "
<< left << setw(14) << diskQueue.front().getFilename() << left << setw(14) << diskQueue.front().getMemoryStart()
<< left << setw(14) << diskQueue.front().getFileLength() << diskQueue.front().getRW() << endl;
diskQueue.pop();
}
}
else
{
cout << left << setw(0) << "" << "0" << left << setw(4) << " "
<< left << setw(14) << " " << left << setw(14) << " "
<< left << setw(14) << " " << " " << endl;
}
}
if( rpdc[0] == 'c' )
{
cout << left << setw(9) << "PID" << left << setw(14) << "Filename"
<< left << setw(12) << "Memstart" << left << setw(14) << "FileLen" << " R/W" << endl;
if( !cdQueue.empty() )
{
for( int i = 0; i < cdQueue.size(); i++ )
{
cout << left << setw(0) << "--c" << i+1 << left << setw(4) << " "
<< left << setw(14) << cdQueue.front().getFilename() << left << setw(14) << cdQueue.front().getMemoryStart()
<< left << setw(14) << cdQueue.front().getFileLength() << cdQueue.front().getRW() << endl;
}
}
else
{
cout << left << setw(0) << "" << "0" << left << setw(4) << " "
<< left << setw(14) << " " << left << setw(14) << " "
<< left << setw(14) << " " << " " << endl;
}
}
}
int PCB::decrementPid()
{
pid--;
}
void PCB::setMemoryStart( int m )
{
memoryLocation = m;
}
int PCB::getMemoryStart() const
{
return memoryLocation;
}
void PCB::setFileLength( int l )
{
fileLen = l;
}
int PCB::getFileLength() const
{
return fileLen;
}
void PCB::setRW( string r )
{
rw = r;
}
string PCB::getRW() const
{
return rw;
}
int main()
{
sysGen s;
PCB p;
s.prompt();
p.runningPrompt();
return 0;
}
Thank you.
