2. check whether a character is an integer or four lines of code from a string to a long integer function.

/************************************ **********************************/
/* 2. check whether a character is an integer or whether four Code ranges from a string to a long integer function */
/** **************************************** * ****************************/
// used to indicate whether to convert valid
bool is_chartointvalid = false;
int chartoint (char ch)
{< br> If (CH> = '0' & Ch <= '9')
is_chartointvalid = true;
return ch-'0 ';
}

// use the database function
long strtolong (const char * Str)
{< br> return atol (STR );
}< br> // four lines of code from a string to a long integer function
long strtolong1 (const char * Str)
{< br> int num = 0;
for (const char * temp = (* STR = '+' | * STR = '-')? STR + 1: Str); * temp> = '0' & * temp <= '9'; ++ temp)
num = 10 * num + * temp-'0';
return (* STR = '-'? -1: 1) * num;
}