명품 c++ 프로그래밍 6장 연습문제 7번

랜덤 실수, 랜덤 알파벳 , 범위가 지정된 정수 

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

class Random {
public:
	static void seed() {srand((unsigned int)time(NULL));}
	static int nextInt(int a, int b);
	static char nextAlphabet();
	static double nextDouble();
};
int Random::nextInt(int a , int b) {
	return (int)((float)rand() / (float)RAND_MAX *(float)(b) + a);
}
char Random::nextAlphabet() {
	int num = 91;
while((num>90 && num<97))
		num = (int)((float)rand() / (float)RAND_MAX *(float)(57) + 65);
	return num;
}
double Random::nextDouble(){
	return ((float)rand() / (float)RAND_MAX );
}

int main() {
	Random::seed();
	cout << "1에서 100까지 랜덤한 정수 10개를 출력합니다" << endl;
	for (int i = 0; i < 10; i++)
		cout << Random::nextInt(1, 100) << ' ';
	cout << endl;
	cout << "알파벳을 랜덤하게 10개를 출력합니다" << endl;
	for (int i = 0; i < 10; i++)
		cout << Random::nextAlphabet() << ' '; cout << endl;
	cout << "랜덤한 실수를 10개를 출력합니다" << endl;
	for (int i = 0; i < 5; i++) 
		cout << Random::nextDouble() << ' ';
	cout << endl;
	for (int i = 0; i < 5; i++)
		cout << Random::nextDouble() << ' ';
	cout << endl;
}