c++ primer 第十七章習題

int main() {
    bitset<32> b1(0x0020212e);
    bitset<32> b2;
    b2.set(1,1);
    b2.set(2,1);
    b2.set(3,1);
    b2.set(5,1);
    b2.set(8,1);
    b2.set(13,1);
    b2.set(21,1);
    cout << b1.to_ulong()<<endl;
    cout << b2.to_ulong()<<endl;
	return 0;
}
 

練習17.11 12 13

class test
{
public:
	void setResult(int i, bool val) {
		b[i] = val;
	}
	test(int x):b(x) {
	}

	bool check(int i) {
		return b[i];
	}

private:
	bitset<100> b;
};

練習17.15

int main() {
    string pattern("[^c]ei");
    pattern = "[[:alpha:]]*"+pattern+"[[:alpha:]]*";
    try{
	    regex r(pattern);
	    smatch results;
	    string test_str;
	    cout << "please input a word: ";
	    while (cin >> test_str){
	        if(regex_search(test_str,results,r))
	    	    cout << results.str() << " violates the rule "<<endl;
	    	else
	    		cout << "it doesn't violate the rule"<<endl;
	    	cout << "please input a word: ";
	    }
	}
    catch(regex_error e) {
    	cout << e.what() << "\ncode: " << e.code() <<endl;
    }
	return 0;
}
 

練習17.16 只會輸出匹配的部分
練習17.17

int main() {
    string pattern("[^c]ei");
    pattern = "[[:alpha:]]*"+pattern+"[[:alpha:]]*";
    try{
	    regex r(pattern);
	    smatch results;
	    string test_str = "hello albeit freind receipt ";
	    for(sregex_iterator it(test_str.begin(),test_str.end(),r),end_it; it != end_it; it++) {
	    	cout << it->str()<<endl;
	    }
	}
    catch(regex_error e) {
    	cout << e.what() << "\ncode: " << e.code() <<endl;
    }
	return 0;
}
 

練習17.23

int main() {
    string pattern("[^c]ei");
    pattern = "(\\d{5})([-]?\\d{4})?";
    try{
	    regex r(pattern);
	    smatch results;
	    string test_str = "543214321";
	    for(sregex_iterator it(test_str.begin(),test_str.end(),r),end_it; it != end_it; it++) {
	    	cout << it->str()<<endl;
	    }
	}
    catch(regex_error e) {
    	cout << e.what() << "\ncode: " << e.code() <<endl;
    }
	return 0;
}

練習17.27

int main() {
    string pattern("[^c]ei");
    pattern = "(\\d{5})([-])?(\\d{4})?";
    try{
	    regex r(pattern);
	    smatch results;
	    string fmt = "$1-$3";
	    string test_str = "54321-4321";
	    cout << regex_replace(test_str,r,fmt);
	}
    catch(regex_error e) {
    	cout << e.what() << "\ncode: " << e.code() <<endl;
    }
	return 0;
}

練習17.28

int randomInt() {
	static default_random_engine e;
	uniform_int_distribution<unsigned> u(0,100);
	return u(e);
}

int main() {
    
    for(int i = 0; i < 10; i++)
    	cout << randomInt()<<endl;
	return 0;
}

練習17.29 30

int randomInt(unsigned int s,unsigned beg, unsigned end) {
	default_random_engine e(s);
	uniform_int_distribution<unsigned> u(beg,end);
	u(e); //此處不先呼叫一次的話返回值都是一樣的，不知為何
	return u(e);
}

int main() {
    
    for(int i = 0; i < 10; i++)
    	cout << randomInt(i+1,10,100)<<endl;
	return 0;
}

練習17.31 每一次得到的結果不變
練習17.32 輸入時出錯