使用cctype库对字符进行方便地判断

/*
cctype字符函数库的使用
*/
#include<iostream>
#include<cctype>
int main() {
	using namespace std;
	cout << "input text for analysis, and type @ to terminate input.\n";
	char ch;
	int whitespace = 0; //空格
	int digits = 0; // 数字
	int chars = 0; // 字符
	int punct = 0; // 标点
	int others = 0;

	cin.get(ch);
	while (ch!='@') {
		if (isalpha(ch))
			chars++;
		else if (isspace(ch))
			whitespace++;
		else if (isdigit(ch))
			digits++;
		else if (ispunct(ch))
			punct++;
		else
			others++;
		cin.get(ch);
	}
	cout << chars << " letters, "
		<< whitespace << " whitespace, "
		<< digits << " digits, "
		<< punct << " punctuations, "
		<< others << " others.\n";

	return 0;
}

输出

input text for analysis, and type @ to terminate input.
i loved a girl 3 years ago, she called me hablee, and i called her yuki. when the days i graduate from master came,
she told me that i can't get a profitable work due to the delay graduation, so we should break up. i am disappointed about the relationship, finally just money issue. So i said, ok,let's break up, then we break up.
@
252 letters, 64 whitespace, 1 digits, 14 punctuations, 0 others.