qstd.cpp

QT4的utils库源码包.解压后运行./configure配置,然后make.使用时在.pro文件中加入两行:LIBS+=-L$$(CPPLIBS)-lutils及INCLUDEPATH+=$$(C

//start id=namespace
#include "qstd.h"

/* QTextStreams look a lot like iostreams,
we just have to point them to the right place. */

//start id=streamdefs
static QTextStream qcin(stdin, QIODevice::ReadOnly);
static QTextStream qcout(stdout, QIODevice::WriteOnly);
static QTextStream qcerr(stderr, QIODevice::WriteOnly);
QTextStream& qstd::cout() {	return qcout; }
QTextStream& qstd::cerr() { return qcerr; }
QTextStream& qstd::cin() { return qcin; }
//end


/* Namespace members are like static class members */
bool qstd::yes(QString question) {
    QString ans;
    cout() << QString(" %1 [y/n]? ").arg(question);
    cout().flush();
    ans = cin().readLine();
    return (ans.toUpper().startsWith("Y", Qt::CaseInsensitive));
}
//end

bool qstd::more(QString s) {
    return yes(QString("Another %1").arg(s));
}


int qstd::promptInt(int base /* =10 */) { /* Usage: int n = promptInt(); */
    QString numstr;
    int result;
    bool ok;
    cout() << ": " << flush;
    while (1) {
        numstr = cin().readLine();
        result = numstr.toInt(&ok, base);
        if (!ok) {
            cout() << "Invalid number. Try again: ";
            cout().flush();
        }
        else
            return result;
    }
}


double qstd::promptDouble() { /* Usage: double d = promptDouble(); */
    QString numstr;
    double result;
    bool ok;
    while (1) {
        numstr = cin().readLine();
        result = numstr.toDouble(&ok);
        if (!ok) {
            cout() << "Invalid number. Try again: ";
            cout().flush();
        }
        else
            return result;
    }
}


void qstd::promptOutputFile(QFile& outfile) {
    QString filename;
    while (1) {
        cout() << "Please enter the file name for saving this data: ";
        cout().flush();
        filename = cin().readLine();
        outfile.setFileName(filename);
        bool fileExists = outfile.open(QIODevice::ReadOnly);
        if (!fileExists) {
            break;
        }
        if (yes("File already exists ... Ok to overwrite"))
            break;
        outfile.close();
    }
    outfile.close();
    outfile.open(QIODevice::WriteOnly);
    cout() << filename << " open for writing ..." << endl;
}


void qstd::promptInputFile(QFile& infile) {
    QString filename;
    while (1) {
        cout() << "Name of the file to be read:  ";
        cout().flush();
        filename = cin().readLine();
        infile.setFileName(filename);
        bool fileExists = infile.open(QIODevice::ReadOnly);
        if (fileExists)
            break;
        cout() << "File does not exist ... Please try again." << endl;
    }
    cout() << infile.fileName() << " open for reading ...\n" << endl;
}