piping urgent help

[vietbong87]

hey i need helpin in pipping a file and using those values in the file to work with the program. ive done the program but it doesnt read the file. can someone help me here.

#include<iostream>
#include<string.h>
using namespace std;

//the cost of the toll gates
const double A_GATE = 2.2;
const double B_GATE = 2.8;
const double C_GATE = 2.3;
const double D_GATE = 3.8;
const string CUSTOMER_TOK = "@";


//Returns the cost of the toll gate
double getTollAmount(string tollGate)
{
	if (tollGate == "A")
		return A_GATE;
	if (tollGate == "B")
		return B_GATE;
	if (tollGate == "C")
		return C_GATE;
	if (tollGate == "D")
		return D_GATE;

	//if it reaches here then its an invalid gate
	cerr << "Invalid Gate: Corrupted tolldata.txt file" << endl;
	return -1;
}


int main() {

	string line;	//line from stdin
	string token1; //id
	string token2; //toll gate or '@'
	string token3; //timestamp or name/address
	string token4; //date
	string token5; //time
	double amount;
	double totalAmount = 0;
	int startPos, endPos;
  
   //read each line from the piped in file
	while(true) {
	
		//read a whole line
		cin >> ws;
		getline(cin, line);
		if(cin.fail()) break; // abort program upon any input failure
		
		startPos = 0;
		endPos = 0;
	
		//get first token
		endPos = line.find("\t");
		token1 = line.substr(startPos, endPos-startPos);
		
		//get next token
		startPos = endPos+1;
		endPos = line.find("\t", startPos);
		token2 = line.substr(startPos, endPos-startPos);

		//get next token
		startPos = endPos+1;
		endPos = line.find("\t", startPos);
		token3 = line.substr(startPos, endPos-startPos);
		
		//start of a new customer
		if (token2 == CUSTOMER_TOK) {
			
			//we just finished processing the previous customer
			if (totalAmount != 0)
				cout << "TOTAL: $" << totalAmount << endl;
				
			totalAmount = 0;
			
			//prints out the header with the customer details
			cout << "\n--INVOICE FOR TOLL EXPENSES--" << endl;
			cout << "-ID-\t\t-Name, Address-" << endl;
			cout << token1 << "\t\t" << token3 << "\n" << endl;
			cout << "-Date-\t\t-Time-\t\t-Station-\t-Amount-" << endl;
		}
		//print the record charged to the customer
		else {
		
			//parse for the date
			startPos = endPos+1;
			endPos = token3.find(":", startPos);
			token4 = token3.substr(startPos, endPos-startPos);

			//parse for the date
			startPos = endPos+1;
			endPos = token3.length();
			token5 = token3.substr(startPos, endPos-startPos);
			
			//get the cost of the toll gate
			amount = getTollAmount(token2);
			totalAmount += amount;
			
			//prints out the record charged details
			cout << token4 << "\t" << token5 << "\t\t" << token2 << "\t\t" << amount << endl;
			
		}//end else
		
	}//end while

	//print the total amount for the last customer
	cout << "TOTAL: $" << totalAmount << endl;
system("pause");
	return 0;
	
}//end main

[WolfPack]

To get the values from the file, you have to open the file. Your program takes values from cin ( which is the standard input ) and outputs results to cout ( which is standard output). To be able to get values from a file. you have to open the file and then replace cin with the pointer for the opened file. Try searching for C++ File Handling tutorials. You will have to use
file open
replace cin with the file you opened
file close

[nanodano]

WolfPack is correct if you want to put the name of the file into your code. From the post, I read that you wanted to pipe a file into it. It would help if you posted your operating system. This is out you can pipe files on a Linux machine:

> output redirect
< input redirect

You could type in a command something like this:

./myprogram < inputfile.dat > outputfile.dat

This would use whatever information is in inputfile.dat as your 'standard input'. Likewise it would redirect your standard output to outputfile.dat.

This way, you can use a file with your program without rewriting the code to open a file.

[WolfPack]

WolfPack is correct if you want to put the name of the file into your code. From the post, I read that you wanted to pipe a file into it. It would help if you posted your operating system. This is out you can pipe files on a Linux machine:

> output redirect
< input redirect

You could type in a command something like this:

./myprogram < inputfile.dat > outputfile.dat

This would use whatever information is in inputfile.dat as your 'standard input'. Likewise it would redirect your standard output to outputfile.dat.

This way, you can use a file with your program without rewriting the code to open a file.

Yes you are correct. You can do that in windows too. Then no need to rewrite the code. Sorry I didnt see the piping part. My mistake.