1
import java.util.Scanner;
public class Main{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
double sum = 0;
int total;
int positive = 0;
int negative = 0;
while(true){
double num = input.nextDouble();
if(num == 0)
break;
sum += num;
if(num > 0)
++positive;
else if(num < 0)
++negative;
}
System.out.println(positive + "\n" + negative + "\n" + sum + "\n" + sum / (positive+negative));
}
}
2
import java.util.Scanner;
public class Main{
public static void main(String[] args){
final int NUMBER_OF_QUESTIONS = 10;
int correctCount = 0;
int count = 0;
long startTime = System.currentTimeMillis();
String output = " ";
Scanner input = new Scanner(System.in);
while(count < NUMBER_OF_QUESTIONS){
int number1 = (int)(Math.random()*15+1);
int number2 = (int)(Math.random()*15+1);
System.out.print("What is " + number1 + " + " + number2 + " ? ");
int answer = input.nextInt();
if(number1 + number2 == answer){
System.out.println("You are correct!");
++correctCount;
}
else
System.out.println("Your answer is wrong.\n" + number1 + " + " + number2
+ " should be " + (number1+number2));
++count;
output += "\n" + number1 + " + " + number2 + " = " + answer +
((number1 + number2 == answer) ? " correct" : " wrong");
}
long endTime = System.currentTimeMillis();
long testTime = endTime - startTime;
System.out.println("Correct count is " + correctCount + "\nTest time is " + testTime/1000
+ " seconds\n" + output);
}
}
3
public class Main {
public static void main(String[] args){
System.out.println("千克 磅");
for(int i = 1; i < 200; ++i){
if(i%2 == 1)
System.out.println(i + " " + i*2.2);
}
}
}
4 5 6
同上
7
import java.util.Scanner;
public class Main{
public static void main(String[] args){
double base = 10000.0;
double num = base;
for(int i = 0; i < 10; ++i){
num += num*0.05;
}
double tuition = num;
double sum = 0.0;
//我从第十一年开始算的
num += num*0.05;
for(int i = 0; i < 4; ++i){
sum += num;
num += num*0.05;
}
System.out.println(tuition);
System.out.println(sum);
}
}
8
import java.util.Scanner;
public class Main{
public static void main(String[] args){
System.out.println("Enter information about ten students");
String[] name = new String[10];
double[] score = new double[10];
Scanner input = new Scanner(System.in);
for(int i = 0; i < 10; ++i){
name[i] = input.next();
score[i] = input.nextDouble();
}
for(int i = 0; i < 10; ++i){
System.out.println(name[i] + ":" + score[i]);
}
}
}
9
import java.util.Scanner;
public class Main{
public static void main(String[] args){
System.out.println("Enter information about ten students");
String[] name = new String[10];
double[] score = new double[10];
Scanner input = new Scanner(System.in);
for(int i = 0; i < 10; ++i){
name[i] = input.next();
score[i] = input.nextDouble();
}
double max;
int temp = 0;
//选择排序法
for(int i = 0; i < 9; ++i){
max = score[i];
temp = i;
for(int j = i + 1; j < 10; ++j){
if(score[j] > max){
max = score[j];
temp = j;
}
}
double tp = score[i];
score[i] = score[temp];
score[temp] = tp;
String tstr = name[i];
name[i] = name[temp];
name[temp] = tstr;
}
for(int i = 0; i < 2; ++i)
System.out.println(name[i] + " : " +score[i]);
}
}
10
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int num = 0;
for(int i = 1; i <= 1000; ++i){
if(i%5 == 0 && i%6 == 0){
System.out.print(i + " ");
++num;
if(num%10 == 0)
System.out.println();
}
}
}
}
11
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int num = 0;
for(int i = 1; i <= 1000; ++i){
if(i%5 == 0 ^ i%6 == 0){
System.out.print(i + " ");
++num;
if(num%10 == 0)
System.out.println();
}
}
}
}
12
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int n = 1;
while(true){
if(n*n > 12000)
break;
++n;
}
System.out.println(n);
}
}
13
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int n = 1;
while(true){
if(n*n > 12000)
break;
++n;
}
System.out.println(n-1);
}
}
14
import java.util.Scanner;
public class Main{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.println("Enter two positive integers");
int num1 = input.nextInt();
int num2 = input.nextInt();
int t = 0;
//辗转相除法
while(true){
t = num1 % num2;
if(t == 0)
break;
num1 = num2;
num2 = t;
}
System.out.println(num2);
}
}
15
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int start = (int)'!';
int end = (int)'~';
for(int i = start; i <= end; ++i){
System.out.print((char)i + " ");
if((i-start+1)%10 == 0)
System.out.println();
}
}
}
16
import java.util.Scanner;
public class Main{
//素数表
static int[] primeNumber = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,
83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,
193,197,199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,
313,317,331,337,347,349,353,359,367,373,379,383,389,397,401,409,419,421,431,433,439,
443,449,457,461,463,467,479,487,491,499,503,509,521,523,541,547,557,563,569,571,577,
587,593,599,601,607,613,617,619,631,641,643,647,653,659,661,673,677,683,691,701,709,
719,727,733,739,743,751,757,761,769,773,787,797,809,811,821,823,827,829,839,853,857,
859,863,877,881,883,887,907,911,919,929,937,941,947,953,967,971,977,983,991,997};
public static void main(String[] args){
Scanner input = new Scanner(System.in);
int num = input.nextInt();
int renum = num;
int[] nums = new int[100];
int i = 0;
int cur = 0;
//测试的时候不要输入素数
//不要害怕找不到结果，因为有下边那句话
//唯一分解定理：任何一个大于1的自然数 N,如果N不为质数，那么N可以唯一分解成有限个质数的乘积
while(true){
if(num > primeNumber[i] && renum%primeNumber[i] == 0){
nums[cur] = primeNumber[i];
++cur;
renum = renum / primeNumber[i];
if(renum == 1)
break;
}
else if(renum%primeNumber[i] != 0){
++i;
}
}
for(int j = 0; j < cur; ++j)
System.out.print(nums[j] + " ");
}
}
17 18 19
.....................虐人的循环语句大集合-----博客链接：http://www.dgcontinent.com/?p=112
20
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int time = 0;
for(int i = 2; i <= 1000; ++i){
if(isPrimeNumber(i)){
System.out.print(i + " ");
++time;
if(time % 8 == 0)
System.out.println();
}
}
}
static boolean isPrimeNumber(int n){
for(int i = 2; i*i <= n; ++i){
if(n % i == 0)
return false;
}
return true;
}
}
21
import java.util.Scanner;
public class Main{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.print("Loan Account:");
double account = input.nextDouble();
System.out.print("Number of Years:");
int year = input.nextInt();
System.out.println("Interests Rate Monthly Payment Total Payment");
double srate = 0.05;
double mrate = 0.05/12;
double erate = 0.08;
double increase = 0.01/8.0;
int acc = 0;
while(true){
++acc;
double monthlyPayment = (account*mrate)/(1-1/Math.pow(1+mrate, year*12));
double totalPayment = monthlyPayment*12.0*year;
System.out.printf("%.3f%% %.2f %.2f\n",srate*100,monthlyPayment,totalPayment);
srate += increase;
mrate = srate/12;
if(acc == 25)
break;
}
}
}
22
参考上一题
23
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int n = 50000;
double sum1 = 0.0;
double sum2 = 0.0;
while(n > 0){
sum1 += 1.0/n;
n--;
}
n = 50000;
for(int i = 1; i <= n; ++i){
sum2 += 1.0/i;
}
System.out.println("From right to left:" + sum1);
System.out.println("From left to right:" + sum2);
}
}
24
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int numerator = 1;
int denominator = 3;
double sum = 0.0;
while(true){
sum += (double)numerator/(double)denominator;
if(denominator == 99)
break;
numerator += 2;
denominator += 2;
}
System.out.println(sum);
}
}
25
import java.util.Scanner;
public class Main{
public static void main(String[] args){
double pi = 0.0;
double[] nums = new double[10];
double molecule = 1.0;
for(int i = 1; i <= 100000; ++i){
pi += molecule/(2*i-1);
molecule = -molecule;
if(i%10000 == 0){
nums[(i/10000)-1] = 4*pi;
}
}
for(int i = 0; i < 10; ++i)
System.out.println(nums[i]);
}
}
26
import java.util.Scanner;
public class Main{
public static void main(String[] args){
double e = 0.0;
double factor = 1.0;
double[] nums = new double[10];
for(int i = 1; i <= 100000; ++i){
e += factor;
factor /= i;
if(i % 10000 == 0)
nums[i/10000-1] = e;
}
for(int i = 0; i < 10; ++i)
System.out.println(nums[i]);
}
}
27
import java.util.Scanner;
public class Main{
public static void main(String[] args){
int cun = 0;
for(int i = 101; i <= 2100; ++i){
if(isLeapYear(i)){
++cun;
System.out.print(i + " ");
if(cun % 10 == 0)
System.out.println();
}
}
System.out.println("\nThe number of leap year:" + cun);
}
static boolean isLeapYear(int n){
if((n%400 == 0) || (n%4 == 0 && n%100 != 0))
return true;
return false;
}
}
28import java.util.Scanner;public class Main{public static void main(String[] args){int[] days = {31,28,31,30,31,30,31,31,30,31,30,31};String[] weeks = {"Sunday","Monday","Tudeday","Wednesday","Thursday","Friday","Saturday"};String[] months = {"January","February","March","April","May" ,"June","July","August","September","October","November","December"};Scanner cin = new Scanner(System.in);int year = cin.nextInt();int week = cin.nextInt();if(isLeapYear(year) && days[1] == 28)++days[1];if(!isLeapYear(year) && days[1] == 29)--days[1];int sum = 1;for(int i = 0; i < 12; ++i){System.out.println(months[i] + " " + "1," + year +" is " + weeks[(sum-1+week)%7]);sum += days[i];}}static boolean isLeapYear(int n){if((n%400 == 0) || (n%4 == 0 && n%100 != 0))return true;return false;}}29.import java.util.*;public class Main { public static void main(String[] args){ CalendarBean cb = new CalendarBean(2016,12); String[] a = cb.getCalendar(); for(int i = 0; i < a.length; ++i){ if(i%7 == 0) System.out.println(); System.out.printf("%4s", a[i]); } }}class CalendarBean{ int year = 0; int month = 0; public CalendarBean(){ this.year = this.month = 0; } public CalendarBean(int year, int month){ this.year = year; this.month = month; } public void setYear(int year){ this.year = year; } public void setMonth(int month){ this.month = month; } public String[] getCalendar(){ String[] a = new String[42]; Calendar rili = Calendar.getInstance(); rili.set(year,month-1, 1); int weekDay = rili.get(Calendar.DAY_OF_WEEK) - 1; int day = 0; if(month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 1) day = 31; if(month == 4 || month == 6 || month == 9 || month == 12) day = 30; if(month == 2){ if((year%4 == 0 && year%100 != 0) || (year%400 == 0)) day = 29; else day = 28; } for(int i = 0; i < weekDay; ++i) a[i] = " "; for(int i = weekDay, n = 1; i < weekDay + day; ++i){ a[i] = String.valueOf(n); ++n; } for(int i = weekDay+day; i < a.length; ++i) a[i] = " "; return a; }}30import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);double money = cin.nextDouble();double interestRate = cin.nextDouble();int month = cin.nextInt();interestRate = interestRate / 100.0;interestRate = interestRate / 12.0;for(int i = 0; i < month; ++i){if(i != 0) money += 100;money = money + money*interestRate;}System.out.println(money);}}31同上32程序清单3-833import java.util.Scanner;public class Main {public static void main(String[] args){for(int i = 6; i <= 10000; ++i){double flag = 0;for(int f = 1; f <= Math.sqrt(i); ++f){if(i%f == 0){flag += f;if(i/f != i)flag += i/f;}}if(flag == i)System.out.println(i);}}}34编程练习题3.1735import java.util.Scanner;public class Main {public static void main(String[] args){double res = 0;for(int i = 2; i <= 625; ++i){res += 1/(Math.sqrt(i-1) + Math.sqrt(i));}System.out.println(res);}}36编程练习题3.937import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);int num = cin.nextInt();int[] arr = new int[64];int len = 0;while(num != 0){arr[len++] = num%2;num = num/2;}for(int i = len-1; i >= 0; --i){System.out.print(arr[i]);}}}38import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);int num = cin.nextInt();int[] arr = new int[64];int len = 0;while(num != 0){arr[len++] = num%8;num = num/8;}for(int i = len-1; i >= 0; --i){System.out.print(arr[i]);}}}39import java.util.Scanner;public class Main {public static void main(String[] args){double one = 5000;double two = 5000;double goal = 30000;double res = (goal - one*0.08 - two*0.1)/0.12;System.out.println(res);}}40。。41import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);int max = Integer.MIN_VALUE;int count = 0;int num = 0;while(cin.hasNext()){num = cin.nextInt();if(num == 0) break;if(num == max){ ++count;continue;}if(num > max){ max = num;count = 1;}}System.out.println(count);}}42。。43import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);int cnt = 0;for(int i = 1; i <= 7; ++i){for(int j = i+1; j <= 7; ++j){System.out.println(i + " " + j);++cnt;}}System.out.println("----" + cnt + "----");}}44import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);int num = cin.nextInt();for(int i = 15; i >= 0; --i){if((num & (1 << i)) != 0)System.out.print(1);elseSystem.out.print(0);}System.out.println();}}45。。46import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);String str = cin.nextLine();StringBuffer strBuf = new StringBuffer(str);System.out.println(strBuf.reverse());}}47。。48import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);String str = cin.nextLine();for(int i = 0; i < str.length(); ++i){if(i%2 == 0)System.out.print(str.charAt(i));}System.out.println();}}49import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);System.out.print("Enter a string:");String str = cin.nextLine();int len = str.length();int vowel = 0;int consonant = 0;for(int i = 0; i < len; ++i){String s = str.charAt(i) + "";if(s.equalsIgnoreCase("A") || s.equalsIgnoreCase("E") || s.equalsIgnoreCase("I") || s.equalsIgnoreCase("O")|| s.equalsIgnoreCase("U")){++vowel;}else{++consonant;}}System.out.println("vowel:" + vowel);System.out.println("consonant:" + consonant);}}50import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);System.out.print("Enter a string:");String str = cin.nextLine();int len = str.length();int num = 0;for(int i = 0; i < len; ++i){Character ch = str.charAt(i);if(ch.isUpperCase(ch)) ++num;}System.out.println("uppercase:" + num);}}51import java.util.Scanner;public class Main {public static void main(String[] args){Scanner cin = new Scanner(System.in);System.out.print("Enter the first string:");String str1 = cin.nextLine();System.out.print("Enter the second string:");String str2 = cin.nextLine();int i = 0;int j = 0;int len = 0;int len1 = str1.length();int len2 = str2.length();while(i < len1 && j < len2){if(str1.charAt(i) == str2.charAt(j)){++len;++i;++j;}elsebreak;}if(len == 0){System.out.println("no common prefix");}else{for(i = 0; i < len; ++i)System.out.print(str1.charAt(i));System.out.println();}}}
