A summary of string and digital mutual transfer in C + +

I. Digital to char* type

1.sprintf functions (suitable for C and C + +)

Example:

Char str[50];   int num = 345;   sprintf (str, "%d", num);

The function of the sprintf () function is very powerful, and here just converts the int number to a string, and more about it is visible: 339254

Two. Digital to String type

1. Using StringStream (only for C + +)

Example:

   String str;   int num = 345;   StringStream SS; Remember to include header files #include<sstream>   ss << Num;   str = SS.STR ();

2. Use To_string (only for C + + and must be c++11 and above)

Example:

   String str;   int num = 345;   str = to_string (num);

Three. char* to Digital

1.atoi and related functions (suitable for C and C + +)

Example:

   Char str[] = "345";   int num;   num = atoi (str);

Related functions include: The C standard library also provides atoi, Atof, Atol, Atoll (C++11 standard) functions to convert strings to int,double, long, long long.

2.sscanf function

Example:

   Char str[] = "345";   int num;   SSCANF (str, "%d", &num);

The function of the SSCANF function is also very powerful, the specific usage is not detailed here.

Four. String to number

1.stoi function (only for C + +)

Example:

   String str = "345";   int num;   num = Stoi (str);

The difference between the Stoi function and the Atoi function is shown in the bottom part of the http://www.cnblogs.com/wangkundentisy/p/8511119.html.

2. Using StringStream (only for C + +)

Example:

   String str = "345";   int num;   StringStream SS;   SS << Str;   SS >> Num;

With StringStream, you can convert a string to a number, and you can convert a number to a string.

One thing to note: Be sure to figure out whether the string is a char * type or a string type.

A summary of string and digital mutual transfer in C + +