Conversion.md

char *itoa( int value, char *string,int radix);

value: 欲转换的数据; string: 目标字符串的地址, radix: 转换后的进制数 , 可以是10进制, 16进制等;

int nNum = 22;
char szNum[32] = {0};
itoa(nNum,szNum,16);

int atoi (const char * str);

char szNum[] = "12345";
int nNum = atoi(szNum);

double atof (const char* str);

char *szNumA="-100.23";   
char *szNumB="200e-2";   
double lfNum;   
lfNum = atof(szNumA) + atof(szNumB);   

int sprintf( char *buffer, const char *format, [ argument] … );

buffer: char型指针, 指向将要写入的字符串的缓冲区; format: 格式化字符串; [argument]...: 可选参数, 可以是任何类型的数据; 返回值: 字符串长度(strlen)

int nNum = 22;
char szNum[32] = {0};
int nLength = sprintf(szNum, "%0d", nNum); 

stringstream

#include <sstream>
int nNum = 30;
stringstream ssTmp;
ssTmp<<nNum; 
ssTmp<<nNum; 
//string strTmp = ssTmp.str();
string strTmp;
ssTmp>>strTmp;
ssTmp.clear();	//清空stringstream的状态(比如出错等), 真正清空内容需要使用 .str("") 方法
ssTmp.str("");
ssTmp<<strTmp;
ssTmp>>nNum;

int sscanf( string str, string fmt, mixed var1, mixed var2 ... );

char *szDateTime = "2016,05,04 - 15:30";
char szDate[32] = {0};
int nHour, nSec;
sscanf(szDateTime, "%s - %d:%d", szDate, &nHour, &nSec);