to_string() is a library function of <string> header, it is used to convert numeric value (number) to string.

to_string()是<string>標頭的庫函數，用于將數值(數字)轉換為字符串。

Syntax:

句法：

string to_string(numberic_value);

Here,

這里，

• string is the return type i.e. function returns an string object that contains the numeric value in string format.

  string是返回類型，即函數返回一個字符串對象，其中包含字符串格式的數字值。

• numbric_value is the number which can be integer, float, long, double.

  numbric_value是可以為整數，浮點數，長整數，雙精度數的數字。

Example:

例：

#include <iostream>
#include <string>
using namespace std;
int main ()
{
//definition of different types of data type
int intVal =12345;
float floatVal = 123.45f;
long longVal = 123456789;
//converting values to string an printing
cout<<"intVal (string format) : "<<to_string (intVal) <<endl;
cout<<"floatVal (string format) : "<<to_string (floatVal) <<endl;
cout<<"floatVal (string format) : "<<to_string (longVal) <<endl;
return 0;
}

Output

輸出量

    intVal (string format) : 12345
floatVal (string format) : 123.449997
floatVal (string format) : 123456789

Expressions results can also be converted to string directly (as the type of expression’s result is numeric)

表達式結果也可以直接轉換為字符串(因為表達式結果的類型是數字)

Consider the example:

考慮示例：

#include <iostream>
#include <string>
using namespace std;
int main ()
{
cout<<to_string (10+20+30+40) <<endl;
cout<<to_string (10+20+12.34) <<endl;
cout<<to_string (10/20+30*2) <<endl;
return 0;
}

Output

輸出量

    10042.34000060

不使用“使用命名空間std”的函數和對象 (Functions and object without using 'using namespace std')

using namespace std is an statement that tells to the compiler to use namespace named std, if we do not write this statement, then we need to use std:: with all functions, objects.

using namespace std是一條語句，告訴編譯器使用名為std的命名空間，如果我們不編寫此語句，則需要對所有函數，對象使用std :: 。

Consider the example:

考慮示例：

#include <iostream>
#include <string>
int main ()
{
std::cout<<std::to_string (10+20+30+40) <<std::endl;
std::cout<<std::to_string (10+20+12.34) <<std::endl;
std::cout<<std::to_string (10/20+30*2) <<std::endl;
return 0;
}

Output

輸出量

    10042.34000060

翻譯自: https://www.includehelp.com/stl/convert-numeric-to-string-using-string-to-string.aspx