Qt中QString和int，char等的“相互”转换

Qt中QString和int，char等的“相互”转换

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1. long a = 63;

2. QString s = QString::number(a, 10); // s == \"63\"

3. QString t = QString::number(a, 16).toUpper(); // t == \"3F\"

(解释，变量a为int型或者float，double。10和16为进制) toUpper是大写

2.使用

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1. long a = 63;

2. QString s = QString(\"%1\").arg(a);

这个嘛，我不常用

把QString转换为 double类型

方法1.

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1. QString str=\"123.45\";

2. double val=str.toDouble(); //val=123.45

方法2.很适合科学计数法形式转换

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1. bool ok;

2. double d;

3. d=QString(\"1234.56e-02\").toDouble(&ok); //ok=true;d;12.3456.

把QString转换为float形

1.

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1. QString str=\"123.45\";

2. float d=str.toFloat(); //d=123.45

2.

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1. QString str=\"R2D2\";

2. bool ok;

3. float d=str.toFloat(&ok); //转换是被时返回0.0,ok=false;

把QString形转换为整形

1.转换为十进制整形

注意：基数默认为10。当基数为10时，并且基数必须在2到36之

间。如果基数为0，若字符串是以0x开头的就会转换为16进制，若以0开头就转换为八进制，否则就转换为十进制。

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1. Qstring str=\"FF\";

2. bool ok;

3. int dec=str.toInt(&ok,10); //dec=255 ; ok=rue

4. int hex =str.toInt(&ok,16); //hex=255;ok=true;

3.常整形转换为Qstring形

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1. long a =63;

2. QString str=QString::number(a,16); //str=\"3f\";

3. QString str=QString::number(a,16).toUpper(); //str=\"3F\";

Qstring 转换char*问题!

方法一:

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1. QString qstr(\"hello,word\");

2. const char * p = qstr.toLocal8Bit().data();

方法二:

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1. const char *p = qstr.toStdString().data();

转换过来的是常量

把当前时间转化为QString...

public QDateTime qdate = QDateTime.currentDateTime();

datetime = qdate.toString(\"yyyy年MM月dd日ddddhh:mm:ss\");

如果不是QTime和QDate类比如说：通过TCP/IP接收到的char unsigned char 类等如何转换为QString类

QString Time2String( DWORD dwTime)

{

char cTime[50] = {0};

memset(cTime,0,50);

strftime(cTime,32,\"%Y-%m-%d %H:%M:%S\

return QString(cTime);

}

由于我采用Qt来写的界面，所以用到了QString类型

1. QString和string的相互转换

[cpp] view plaincopyprint?

1. //------------------------

2. // QString and string change

3. //------------------------

4. QString s2q(const string &s)

5. {

6. return QString(QString::fromLocal8Bit(s.c_str()));

7. }

8. string q2s(const QString &s)

9. {

10. return string((const char *)s.toLocal8Bit());

11. }

2. QString to Char*

[cpp] view plaincopyprint?

1. QString data;

2. data.toLatin1().data();

3. char to number

[cpp] view plaincopyprint?

1. int char2num(char ch)

2. {

3. if(ch>='0'&&ch<='9')return ch-'0';

4. else if(ch>='a'&&ch<='f')return ch-'a'+10;

5. return -1;

6. }

4. number to QString

[css] view plaincopyprint?

1. QString::number(number,10);//10表示的是进制，如是16进制，则改为16

5. uint8_t to QString

[cpp] view plaincopyprint?

1. uint8_t Message_Digest;

2. QString::number(Message_Digest,16);

6. BYTE* to char[] to QString

[cpp] view plaincopyprint?

1. QString textshow = NULL;

2. BYTE * output = new BYTE[1024];

3. for(int i=0; i<16; i++)

4. {

5. char pBuff[2];

6. sprintf(pBuff,\"%02x\

7. textshow = textshow + pBuff;

8. }

7. string to BYTE [] //其中#define unsigned char BYTE

[cpp] view plaincopyprint?

1. ////-------------------------------------------

2. //// 将字符串类型转换为BYTE数组

3. ////-------------------------------------------

4. void CryptClient::HexStrToByte(string str_arr, BYTE byte_arr[24])

5. {

6. unsigned char ch1;

7. unsigned char ch2;

8. int k = 0;

9. for (int i=0; i10. {

11. ch1 = str_arr.at(i);

12. ch2 = str_arr.at(i+1);

13. if (ch1>=48 && ch1 <= 57)

14. {

15. ch1 &= 0x0F;

16. }

17. if (ch1>='A' && ch1 <='F')

18. {

19. ch1 &= 0x0F;

20. ch1 += 0x09;

21. }

22. if (ch2 >= 48 && ch2 <= 57)

23. {

24. ch2 &= 0x0F;

25. }

26. if (ch2>='A' && ch2 <='F')

27. {

28. ch2 &= 0x0F;

29. ch2 += 0x09;

30. }

31. ch1<<=4;

32. byte_arr[k] = ch1 + ch2;//int类型转byte类型，有问题

33. k++;

34. }

35. }

8. BYTE[] to string //上个过程的逆过程

[c-sharp] view plaincopyprint?

1. ////-------------------------------------------

2. //// 将BYTE数组转换为字符串类型

3. ////-------------------------------------------

4. string* byteToHexStr(BYTE byte_arr[], int arr_len)

5. {

6. string* hexstr = new string;

7. for(int i=0; i8. {

9. char hex1;

10. char hex2;

11. int value = byte_arr[i];

12. int v1 = value/16;

13. int v2 = value % 16;

14. //将商转换为字母

15. if (v1>=0 && v1<=9)

16. {

17. hex1 = (char)(48 + v1);

18. }

19. else

20. {

21. hex1 = (char)(55 + v1);

22. }

23. //将余数转成字母

24. if (v2>=0 && v2<=9)

25. {

26. hex2 = (char)(48 + v2);

27. }

28. else

29. {

30. hex2 = (char)(55 + v2);

31. }

32. //将字母连成一串

33. *hexstr = *hexstr + hex1 + hex2;

34. }

35. return hexstr;

36. }

9. char* to QString

[cpp] view plaincopyprint?

1. QString keyall1;

2. char keych1[MAX_NUM];

3. keyall1 = QString(QLatin1String(keych1));

嗯，基本上程序中就用到了这么多，写出来，留着以后自己参考，要是有人能用到，那就更好啦~~~~~~~~