Chapter 12.3, Problem 12.12CP

Program Plan Intro

“stoi” function:

In C++, the predefined function “stoi” is used to convert a string value into an integer value; it contains three parameters to refer the string to convert, position of first character in the string after the number.

Syntax:

Consider the syntax for the “stoi” function is as follows:

int stoi ( const string& n, size_t* s = 0, int base = 10);

In the above statement,

• “int” represents the return type of the function.
• The first parameter “const string& n” represents the string to be converted.
• The second parameter “size_t* s” represents the position of first character in the string after the number and this argument is an optional one.
• The third parameter “base” represents the base of the conversion and this argument is an optional one.

Example:

Example for the “stoi” function is as follows:

//declare and assign the value to the variable

string s = "5478hai";

//change the string object to an integer value.

int n = stoi(s);

In the above code, the string value “5478hai” stored in the variable “s” is converted into an integer and stored and into the variable “n”; the above statement results the value “5478”.