Chapter 12.3, Problem 12.10CP

Program Plan Intro

“atol” function:

In C++, the predefined function “atol” is used to convert a string value into a long integer value; it passes a string literal or character array as an argument and it converts the received value into a long integer value; it takes only one parameter as an argument.

• If the argument value contains nonconvertible contents combined with the integer value then the values will be ignored while converting.
• In same way, the function will return “0” when the values can’t be able to convert into double data type.

Syntax:

Syntax for “atol” function is as follows:

long int atol (const char* n);

In the above statement,

• “long int” represents the return type of the function.
• “atol” represents the name of the function.
• “const char*” represents the data type of the passing argument.
• “n” is a string variable which is required to be converted.

Example:

The example for the “atol” function is as follows:

//change the string literal to a long type value

long n = atol ("123456 hello");

In the above line, the string literal “123456 hello” is passed as an argument to “atol” and it returns the converted value that is “123456”; here the “atol” function ignores the whitespace and the nonconvertible value “hello”.