c++中数字与字符串之间的转换方法(推荐)

(1)string --> char *
  string str("OK");
  char * p = str.c_str();

(2)char * -->string
  char *p = "OK";
  string str(p);

(3)char * -->CString 
  char *p ="OK";
  CString m_Str(p);
  //或者
  CString m_Str;
  m_Str.Format("%s",p);

(4)CString --> char *
  CString str("OK");
  char * p = str.GetBuffer(0);
  ...
  str.ReleaseBuffer();

(5)string --> CString 
  CString.Format("%s", string.c_str()); 

(6)CString --> string
  string s(CString.GetBuffer(0)); 
  GetBuffer()后一定要ReleaseBuffer()，否则就没有释放缓冲区所占的空间，CString对象不能动态增长了。

(7)double/float->CString
  double data;
  CString.Format("%.2f",data); //保留2位小数

(8)CString->double
  CString s="123.12";
  double  d=atof(s);  
 
(9)string->double
 double d=atof(s.c_str());

char str[10];
int a=1234321;
sprintf(str,"%d",a);
--------------------
char str[10];
double a=123.321;
sprintf(str,"%.3lf",a);
--------------------
char str[10];
int a=175;
sprintf(str,"%x",a);//10进制转换成16进制，如果输出大写的字母是sprintf(str,"%X",a)
--------------------
char *itoa(int value, char* string, int radix); 

char str[]="1234321";
int a;
sscanf(str,"%d",&a);
.............
char str[]="123.321";
double a;
sscanf(str,"%lf",&a);
.............
char str[]="AF";
int a;
sscanf(str,"%x",&a); //16进制转换成10进制

 ostringstream s1;
 int i = 22;
 s1 << "Hello " << i << endl;
 string s2 = s1.str();
 cout << s2;

 istringstream stream1;
 string string1 = "25";
 stream1.str(string1);
 int i;
 stream1 >> i;
 cout << i << endl; // displays 25