P1049 譚浩強C語言(第三版)習題6.5

import java.util.*;
import java.io.*;
import java.math.BigInteger;
import java.lang.Character;

public class Main
{
    public static void main(String args[])
    {
        Scanner cin=new Scanner(System.in);
        int a=cin.nextInt(),b=cin.nextInt(),c=cin.nextInt();
        double ans=0;
        for(int i=1;i<=a;++i)
        {
            ans+=i;
        }
        for(int i=1;i<=b;++i)
        {
            ans+=i*i;
        }
        for(int i=1;i<=c;++i)
        {
            ans=ans+1.0/i;
        }
        System.out.printf("%.2f\n", ans);
    }

}

P1050 譚浩強C語言(第三版)習題6.6

import java.util.*;
import java.io.*;
import java.math.BigInteger;
import java.lang.Character;

public class Main
{
    public static void main(String args[])
    {
        for(int i=100;i<=999;++i)
        {
            int x=i/100, y=(i/10)%10, z=i%10;
            if(x*x*x+y*y*y+z*z*z==i)
            {
                System.out.println(i);
            }
        }
    }
}

P1051 譚浩強C語言(第三版)習題6.7

用了個比較複雜的結構，做的比較醜。

import java.util.*;
import java.io.*;
import java.math.BigInteger;
import java.lang.Character;

public class Main
{
    public static void main(String args[])
    {
        Scanner cin=new Scanner(System.in);
        int n=cin.nextInt();
        for(int k=1;k<=n;++k)
        {
            if(k==1) continue;
            List<Integer> al=new ArrayList<Integer>();
            for(int i=1;i*i<=k;++i)
            {
                if(k%i==0)
                {
                    al.add(i);
                    al.add(k/i);
                }
            }
            int sum=0;
            for(Integer i: al)
                sum+=i; 
            if(sum==k+k)
            {
                Collections.sort(al);
                System.out.printf("%d its factors are ", k);
                for(int i=0;i<al.size()-1;++i) 
                {
                    System.out.print(al.get(i));
                    if(i==al.size()-2) System.out.print(" ");
                    else System.out.print(" ");
                }
                System.out.println();
            }
        }
    }
}

P1052 譚浩強C語言(第三版)習題6.8

import java.util.*;
import java.io.*;
import java.math.BigInteger;
import java.lang.Character;

public class Main
{
    public static void main(String args[])
    {
        Scanner cin=new Scanner(System.in);
        int n=cin.nextInt();
        int a=2,b=1,tmp;
        double ans=0;
        for(int i=1;i<=n;++i)
        {
            //System.out.printf("%d %d\n",a,b);
            ans+=(double)a/b;
            tmp=a;
            a+=b;
            b=tmp;
        }
        System.out.printf("%.2f\n", ans);
    }
}

P1053 譚浩強C語言(第三版)習題6.9

import java.util.*;
import java.io.*;
import java.math.BigInteger;
import java.lang.Character;

public class Main
{
    public static void main(String args[])
    {
        Scanner cin=new Scanner(System.in);
        int m=cin.nextInt(),n=cin.nextInt();
        double ans=0,now=m;
        for(int i=1;i<=n;++i)
        {
            if(i==1) ans+=now;
            else ans+=now*2;
            now/=2.0;
        }
        System.out.printf("%.2f %.2f\n", now, ans);
    }
}