如何将QString转换为char *或者相反

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如何将QString转换为char *或者相反

官方：

How can I convert a QString to char* and vice versa ?(trolltech)

Answer:
In order to convert a QString to a char*, then you first need to get a latin1 representation of the string by calling toLatin1() on it which will return a QByteArray. Then call data() on the QByteArray to get a pointer to the data stored in the byte array. See the documentation:

See the following example for a demonstration:

int main(int argc, char **argv)
{
QApplication app(argc, argv);
QString str1 = "Test";
QByteArray ba = str1.toLatin1();
const char *c_str2 = ba.data();
printf("str2: %s", c_str2);
return app.exec(); 
}
Note that it is necessary to store the bytearray before you call data() on it, a call like the following
const char *c_str2 = str2.toLatin1().data();

will make the application crash as the QByteArray has not been stored and hence no longer exists.

To convert a char* to a QString you can use the QString constructor that takes a QLatin1String, e.g:

QString string = QString(QLatin1String(c_str2)) ;

网上版本

char * 与 const char *的转换
char *ch1="hello11";
const char *ch2="hello22";
ch2 = ch1;//不报错，但有警告
ch1 = (char *)ch2;


char 转换为 QString
其实方法有很多中，我用的是：
char a='b';
QString str;
str=QString(a);


QString 转换为 char
方法也用很多中
QString str="abc";
char *ch;
ch = str.toLatin1.data();


QByteArray 转换为 char *
char *ch;//不要定义成ch[n];
QByteArray byte;
ch = byte.data();


char * 转换为 QByteArray
char *ch;
QByteArray byte;
byte = QByteArray(ch);


QString 转换为 QByteArray
QByteArray byte;
QString string;
byte = string.toAscii();




QByteArray 转换为 QString
QByteArray byte;
QString string;
string = QString(byte);
这里再对这俩中类型的输出总结一下：
qDebug()<<"print";
qDebug()< qDebug()< qDebug()< qDebug()< qDebug()< qDebug()< 但是qDebug()< qDebug()<

int 转 QString
int a=10;
QString b;
b=QString::number(a)


QString 转int
QString a="120"
int b;
b=a.toInt（）
char * 与 const char *的转换
char *ch1="hello11";
const char *ch2="hello22";
ch2 = ch1;//不报错，但有警告
ch1 = (char *)ch2;


char 转换为 QString
其实方法有很多中，我用的是：
char a='b';
QString str;
str=QString(a);


QString 转换为 char
方法也用很多中
QString str="abc";
char *ch;
ch = str.toLatin1.data();


QByteArray 转换为 char *
char *ch;//不要定义成ch[n];
QByteArray byte;
ch = byte.data();


char * 转换为 QByteArray
char *ch;
QByteArray byte;
byte = QByteArray(ch);


QString 转换为 QByteArray
QByteArray byte;
QString string;
byte = string.toAscii();




QByteArray 转换为 QString
QByteArray byte;
QString string;
string = QString(byte);
这里再对这俩中类型的输出总结一下：
qDebug()<<"print";
qDebug()< qDebug()< qDebug()< qDebug()< qDebug()< qDebug()< 但是qDebug()< qDebug()<

int 转 QString
int a=10;
QString b;
b=QString::number(a)


QString 转int
QString a="120"
int b;
b=a.toInt（）
另一个


1 QString --> string
QString.toStdString();
2 string --> QString
QString::fromStdString(string)
3 QString --->int,double,char *
QString::toInt()
QString::toDouble()
QString.toStdString().c_str();
4 int double char* --->string
可以采用里的stringstream
以int 为例，int a = 3;
stringstream ss;
string strInt;
ss< ss>>strInt;