Not looping Correctly - c++

Question

The purpose of this code it to be a basic Library check-in check-out system, I use a scanner to input a barcode which is the ISBN number then the program looks at my .txt database and searches for the book name. Then it asks you if you would like to check out the book and asks for student ID number and then outputs ISBN, out/in, id number and current time to a FILE. The program works great the first time but then if you try to check out another book after inputting the barcode it will stop working. It wont take input cant move on just stops.
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <ctime>
using namespace std;
int main()
{
char variable = 1;
ifstream infile;
ofstream outfile;
infile.open("Library_Database.txt");
outfile.open("Library_Checkout.txt", ios::app);
do {
char variable;
cout << "SETSUCON MANGA LIBRARY DATABASE\n\n" << setw(45) << "For Check-Out please enter: O or o\n" << setw(45) << "For Check-In please enter: I or i\n" << setw(45) << "For Assistance please enter: H or h\n" << setw(45) << "To close this program please enter: Q or q\n" << setw(50) << "Enter an option: ";
cin >> variable;
cout << "\n";
if (variable == 'O' || variable == 'o'){
double search;
double ISBN = 0;
string bookName;
cout << "Please Scan Barcode: ";
cin >> search; //runs fine one time then gets stuck here after I input the ISBN number the second time
while (ISBN != search){
infile >> ISBN >> bookName;
}
cout << "You would like to check out: " << bookName << "?" << endl;
string idNumber;
char yesOrNo;
cout << "Yes or No (Y or N): ";
cin >> yesOrNo;
if (yesOrNo == 'Y' || yesOrNo == 'y'){
cout << "Please input Student ID number or Badge ID Number: ";
cin >> idNumber;
cout << endl;
time_t now = time(0);
char* dt = ctime(&now);
outfile.setf(ios::fixed);
outfile.precision(0);
outfile << search << std::resetiosflags(std::ios::showbase) << setw(12) << idNumber << setw(4) << "out" << setw(30) << dt << endl;
}
else{
cout << endl << "\n";
continue;
}
}
else if (variable == 'I' || variable == 'i'){
double search;
double ISBN = 0;
string bookName;
cout << "Please Scan Barcode: ";
cin >> search; //runs fine one time then gets stuck here after I input the ISBN number the second time
while (ISBN != search){
infile >> ISBN >> bookName;
}
cout << "You would like to check in: " << bookName << "?" << endl;
string idNumber;
char yesOrNo;
cout << "Yes or No (Y or N): ";
cin >> yesOrNo;
if (yesOrNo == 'Y' || yesOrNo == 'y'){
cout << "Please input Student ID number or Badge ID Number: ";
cin >> idNumber;
cout << endl;
time_t now = time(0);
char* dt = ctime(&now);
outfile.setf(ios::fixed);
outfile.precision(0);
outfile << search << std::resetiosflags(std::ios::showbase) << setw(12) << idNumber << setw(4) << "in" << setw(30) << dt << endl;
}
else{
cout << endl << "\n";
continue;
}
}
else if (variable == 'H' || variable == 'h'){
cout << "This program was written Shea Transue.\n" << "For Assistance Please Contact Shea Transue at 484-264-5863\n\n";
}
else if (variable == 'Q' || variable == 'q') {
cout << "Thank you for using the SETSUCON LIBRARY DATABASE.\n" << "For assistance please Call or Text Shea Transue at 484-264-5864\n\n";
break;
}
else {
cout << variable << " is not a valid option. Try again\n\n";
}
} while (variable != 'Q' || variable != 'q');
infile.close();
outfile.close();
return 0;
}

Answer 1

You open the library database infile and scan through it with the >> operator, but you never seek back to the beginning with infile.seekg( 0, std::ios::beg ).
When any book isn't found, the while loop never terminates. Since you only start scanning the database from somewhere in the middle, any book after the first may not be found.
Try this:
do {
cout << "Please Scan Barcode: ";
cin >> search; //runs fine one time then gets stuck here after I input the ISBN number the second time
infile.clear();
infile.seekg( 0, std::ios::beg );
while ( infile && ISBN != search){
infile >> ISBN >> bookName;
}
if ( ! infile ) {
std::cout << "The book was not found in the database.\n";
}
} while ( ! infile );
Also, try dividing ("factoring") the program into separate functions, and test each function separately.