一、標準C下的數字和字符串間的轉換通過ssprinf和sscanf來實現的。示例如下：
int Number = 123; // number to convert
char Result[16]; // string which will contain the number
sprintf ( Result, "%d", Number ); // %d makes the result be a decimal integer (%d業可寫成%x(16進制)%h(8進制))
char Text[] = "456"; // string to be converted
int Result; // number which will contain the result
sscanf ( Text, "%d", &Result );
二．C++的字符串時string類，它的轉換和標C是完全不同的，主要通過ostringstream和istringstream實現。
int Number = 123; // number to be converted to a string
string Result; // string which will contain the result
ostringstream convert; // stream used for the conversion
convert << Number; // insert the textual representation of 'Number' in the characters in the stream;
Result = convert.str(); // set 'Result' to the contents of the stream
string String = static_cast<ostringstream*>( &(ostringstream() << hex << Number) )->str();//Convert string(hexadecimal base)
string Text = "456"; // string containing the number
int Result; //number which will contain the result
istringstream convert(Text); // stringstream used for the conversion constructed with the contents of 'Text' // ie: the stream will start containing the characters of 'Text'
if ( !(convert >> hex >> Result) ) //give the value to 'Result' using the characters in the stream(hexadecimal base)
Result = 0; //if that fails set 'Result' to 0
我們也可以用自定義的模板實現
template <typename T>
string NumberToString ( T Number )
{
ostringstream ss;
ss << Number;
return ss.str();
}
Usage: NumberToString ( Number );
template <typename T>
T StringToNumber ( const string &Text )
{
istringstream ss(Text);
T result;
return ss >> result ? result : 0;
}
Usage: StringToNumber<Type> ( String );
上面的方法適用于各種C++平臺，包括linux和windows，ostringstream需要包含的頭文件是sstream。
也可以用sprintf來拼字符串，例如：
int t_iArrray[2]={1,3};
string t_sTemp;
sprintf((char*)t_sTemp.c_str(),"%d.%d",t_iArray[0],t_iArray[1]);
但注意的是cout<<t_sTemp<<endl和cout<<t_sTemp.c_str()<<endl;后者可以正確輸出，前者是空值。
sprintf只是將拼接的字符串結果保存在 t_sTemp.c_str()，而非t_sTemp.