fast reading example

inline int (void);
inline int read_unsigned(void);

int main(void) {
	
	int a = read();
	int b = read_unsigned();
	//	DO NOT use something like:
	//	int a = read(), b = read();
	//	it will NOT work CORRECTLY
	int c = read();
	int d = read_unsigned();
	
	printf("a = %2dn"
		   "b = %2dn"
		   "c = %2dn"
		   "d = %2dn", 
			a, b, c, d
	);
	/*	Output :
			a =  2
			b =  2
			c = -2	
			d =  2	// the input for c is -2, but read_unsigned() will drop the '-'
	*/
	return 0;
}

#include<cctype>
//	provide isdigit(),
//	which can judge whether a char
//	is a digit	-> returns true
//	or not		-> returns false

/*
	*	read() & read_unsigned()
	*	@brief	Read a number.
	*	@return	read() returns the next number in the buffer.
	*			read_unsigned() returns the number with no sign
	*
	*	Read a number digit by digit.
	*	Much FASTER than scanf() ONLY when you need to read a LARGE NUMBER of numbers.
	*	read_unsigned() is NOT ABLE to read NEGATIVE number.
	*
	*	Example: 123 =>	1			= 1
	*					1 * 10 + 2	= 12
	*					12 * 10 + 3 = 123
	*	
	*	Code Author : Xeon.Stin.
*/

inline int (void) {
	char ch;
	while (!(isdigit(ch = getchar()) || ch == '-'));	
	//	judge whether the number is negative
	int res = 0, flg = 1;
	//	and get rid of those not-digit chars
	if (ch == '-') flg = -1;
	//	judge whether the number is negative
	else res = ch - '0';	
	//	the first digit of number
	while (isdigit(ch = getchar()))
	//	read the other digits of number
		(res *= 10) += ch - '0';	
	//	means: res = res * 10 + ch - '0';
	return res * flg;
	//	returns a signed number
}

inline int read_unsigned(void) {
	char ch;
	while (!isdigit(ch = getchar()));	//	get rid of those not-digit chars
	int res = ch - '0';					//	the first digit of number
	while (isdigit(ch = getchar()))		//	read the other digits of number
		(res *= 10) += ch - '0';		//	means: res = res * 10 + ch - '0';
	return res;							//	returns a unsigned number
}