C Reference function atol()

This function of stdlib will convert a string to a long integer.

Usage of atol():

long int atol ( const char * str );

Parameters:

C string str interpreting its content as a integer. White-spaces are discarded until the first non-whitespace character is found.

Return value:

The function returns the converted integral number as an int value, if successful and returns it as a long int. If no valid conversion could be performed then an zero value is returned.
If the value is out of range then LONG_MAX or LONG_MIN is returned.

Source code example of atol():

	#include<stdio.h>
	#include<stdlib.h>

	int main ()
	{
		long int long_int;
		char buffer [256];

		printf ("Enter a long number: ");
		gets ( buffer );

		long_int = atol (buffer);
		printf ("The value entered is %d.\n",long_int);

		return 0;
	}

Output of the atol example program above:

	Enter a long number: 256000
	The value entered is 256000.