<style>

html, body, .ui-content {
background-color: #333;
color: #ddd;
}

body > .ui-infobar {
display: none;
}

.ui-view-area > .ui-infobar {
display: block;
}

.markdown-body h1{
color: #9CCEF2;
}
.markdown-body h2,
.markdown-body h3{
color: #B1D6CA;
}
.markdown-body h4,
.markdown-body h5,
.markdown-body h6 {
color: #ddd;
}

.markdown-body h1,
.markdown-body h2 {
border-bottom-color: #ffffff69;
}

.markdown-body h1 .octicon-link,
.markdown-body h2 .octicon-link,
.markdown-body h3 .octicon-link,
.markdown-body h4 .octicon-link,
.markdown-body h5 .octicon-link,
.markdown-body h6 .octicon-link {
color: #fff;
}

.markdown-body img {
background-color: transparent;
}

.ui-toc-dropdown .nav>.active:focus>a, .ui-toc-dropdown .nav>.active:hover>a, .ui-toc-dropdown .nav>.active>a {
color: white;
border-left: 2px solid white;
}

.expand-toggle:hover,
.expand-toggle:focus,
.back-to-top:hover,
.back-to-top:focus,
.go-to-bottom:hover,
.go-to-bottom:focus {
color: white;
}

.ui-toc-dropdown {
background-color: #333;
}

.ui-toc-label.btn {
background-color: #191919;
color: white;
}

.ui-toc-dropdown .nav>li>a:focus,
.ui-toc-dropdown .nav>li>a:hover {
color: white;
border-left: 1px solid white;
}

.markdown-body blockquote {
color: #bcbcbc;
}

.markdown-body table tr {
background-color: #5f5f5f;
}

.markdown-body table tr:nth-child(2n) {
background-color: #4f4f4f;
}

.markdown-body code,
.markdown-body tt {
color: #eee;
background-color: rgba(230, 230, 230, 0.36);
}

a,
.open-files-container li.selected a {
color: #5EB7E0;
}

</style>

###### tags: `tgirc早修book`

# Ch.02 題目練習

## if else

<font color="FEA0A0">**題目**</font>
1. [Zerojudge d064: ㄑㄧˊ 數？](https://zerojudge.tw/ShowProblem?problemid=d064)
2. [Zerojudge a003: 兩光法師占卜術](https://zerojudge.tw/ShowProblem?problemid=a003)
3. [Zerojudge d485: 我愛偶數](https://zerojudge.tw/ShowProblem?problemid=d485)
4. [Zerojudge d065: 三人行必有我師](https://zerojudge.tw/ShowProblem?problemid=d065)
5. [Zerojudge d066: 上學去吧！](https://zerojudge.tw/ShowProblem?problemid=d066)
6. [Zerojudge a006: 一元二次方程式](https://zerojudge.tw/ShowProblem?problemid=a006)

:::spoiler <font color="FEA0A0">**題解**</font>

1. [Zerojudge d064: ㄑㄧˊ 數？](https://zerojudge.tw/ShowProblem?problemid=d064)

#include<iostream>
using namespace std;

int main(){
	int n;
	cin >> n;
    
    if(n % 2 ==0){
        cout << "Even";
    }
    else{
        cout << "Odd";
    }
    
	return 0;
}

##

2. [Zerojudge a003: 兩光法師占卜術](https://zerojudge.tw/ShowProblem?problemid=a003)

#include <iostream>
using namespace std;
 
int main()
{
    int M, D, S;
    cin >> M >> D;
    
    S = (M * 2 + D) % 3;
    
    if (S == 0){
        cout << "普通\n";
    }
    else if (S == 1){
        cout << "吉\n";
    }
    else {
        cout << "大吉\n";
    }
    
    return 0;
}

##

3. [Zerojudge d485: 我愛偶數](https://zerojudge.tw/ShowProblem?problemid=d485)

#include<iostream>
using namespace std;

int main(){
	int a, b, ans;
	cin >> a >> b;
    
	ans = b/2 - a/2;
	ans += (a+1)%2;
    
	cout << ans;
	
	return 0;
}

##

4. [Zerojudge d065: 三人行必有我師](https://zerojudge.tw/ShowProblem?problemid=d065)

#include<iostream>
using namespace std;

int main(){
	int in, max=0;
    
	for(int i = 0; i < 3; i++){
		cin >> in;
		if(in > max){
            max = in;
        }
    }
    
	cout << max;
	return 0;
}

##

5. [Zerojudge d066: 上學去吧！](https://zerojudge.tw/ShowProblem?problemid=d066)

#include<iostream>
using namespace std;

int main(){
	int hh, mm;
	cin >> hh >> mm;
	
	if(hh>=8 && hh<=16){
		cout << "At School" << endl;
	}
	else if(hh == 7){
		if(mm >= 30){
			cout << "At School" << endl;
		}
		else{
			cout << "Off School" << endl;
		}
	}
	else{
		cout << "Off School" << endl;
	}
	
	return 0;
}

##

6. [Zerojudge a006: 一元二次方程式](https://zerojudge.tw/ShowProblem?problemid=a006)

#include<iostream>
#include<cmath> 
using namespace std;

int main(){
	int a, b, c;
	int x1, x2;	 //兩解 
	int d;		 //判別式
	cin >> a >> b >> c;
	
	d = sqrt( b*b - 4*a*c );    //判別式
	
	if(d>0){	        //判別式>0，兩實根 
		x1 = (-b + d) / (2*a);
		x2 = (-b - d) / (2*a);
		
		cout << "Two different roots x1=" << x1 << " , x2=" << x2;
	}
	else if(d == 0){    //判別式=0，重根 
		x1 = (-b) / (2*a);
		
		cout << "Two same roots x=" << x1;
	}
	else{            //判別式<0，無實根 
		cout << "No real root";
	}
	return 0;
}

:::