Bài Tập Lập Trình JAVA số 1

1.  Đếm ký tự hoa

package baitap_coban;

import java.util.Scanner;

public class Demki_tuhoa {

public static void main(String[] args) {

System.out.println("nhap vao mot chuoi: ");

Scanner scan = new Scanner(System.in);

String str = scan.nextLine();

int dem =0;

for(int i = 0;i<str.length();i++) {

if( str.charAt(i)>='A' && str.charAt(i)<='Z')

dem++;

} 

//return dem ;

System.out.println(" "+dem);

}

}

2.  Tính điểm trong java

package baitap_coban;

import java.util.Scanner;

public class Diem {

public static void main(String[] args) {

System.out.println("nhap diem cua sinh vien: ");

Scanner nhap = new Scanner(System.in);

float a = nhap.nextFloat();

int b = nhap.nextInt();

if (a >= 3.6 && a <= 4.0)

System.out.println("hoc sinh xuat sac");

else if (a >= 3.2 && a < 3.6)

System.out.println("hoc sinh gioi");

else if (a >= 2.5 && a < 3.2)

System.out.println("hoc sinh kha");

else if (a >= 2.0 && a < 2.5)

System.out.println("hoc sinh trung binh");

else if (a >= 0.0 && a < 2.0)

System.out.println("hoc sinh yeu");

else

System.out.println("diem trung binh khong dung");

switch (b) {

case 1:

System.out.println("one");

break;

case 2:

System.out.println("three");

break;

default:

System.out.print("ket thuc");

}

}

}

3. Tính tiền karaoke

package baitap_coban;

import java.util.Scanner;

public class Karaoke {

public static void main(String[] args) {

int start, end;

Scanner nhap = new Scanner(System.in);

System.out.print("gio bat dau: ");

start = nhap.nextInt();

System.out.print("gio ket thuc: ");

end = nhap.nextInt();

if (end < 18) {

System.out.print("tien gio la: " + (end - start) * 45000 + "VND");

} else {

if (start < 18) {

System.out.print("tien gio la: "

+ (((18 - start) * 45000) + ((end - 18) * 60000))

+ "VND");

} else {

System.out.print("tien gio la: " + (end - start) * 60000

+ "VND");

}

}

}

}

4. Thực đơn

package baitap_coban;

import java.util.Arrays;

import java.util.Random;

public class Menu {

public String[] FoodName = { "Tao", "Cherry", "Cam", "Quyt", "Duahau",

"Chanh", "Kiwi", "Nho", "Melon", "DaoTien", "Chuoi", "DauTay",

"Thom", "Le", "Sua", "CaChua", "CaRot", "CaTim", "HanhTay", "Toi",

"KhoaiTay", "Nam", "BanhMy", "Bow", "Bia", "Ngheu", "Cua", "Ca",

"Tom", "Ga", "Bof", "Trung" };

public int[][] Food = { { 0, 0, 1, 1, 0, 0, 0, 0, 0, 0 },

{ 0, 0, 1, 0, 0, 0, 1, 1, 0, 0 }, { 0, 0, 1, 0, 0, 0, 0, 0, 1, 1 },

{ 0, 0, 1, 1, 1, 0, 0, 0, 0, 1 }, { 0, 0, 1, 0, 0, 0, 0, 1, 0, 0 },

{ 0, 0, 0, 1, 0, 0, 1, 0, 0, 1 }, { 0, 0, 1, 1, 1, 0, 0, 1, 0, 1 },

{ 0, 0, 1, 0, 0, 1, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0, 1, 1, 0, 1, 0 },

{ 0, 0, 1, 1, 0, 1, 0, 0, 0, 0 }, { 0, 0, 1, 0, 0, 1, 0, 0, 0, 1 },

{ 0, 0, 1, 1, 0, 0, 1, 0, 0, 1 }, { 0, 0, 1, 0, 0, 0, 0, 0, 1, 0 },

{ 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 }, { 1, 1, 1, 0, 1, 1, 0, 1, 0, 0 },

{ 0, 0, 1, 0, 0, 1, 0, 1, 0, 1 }, { 0, 0, 1, 1, 0, 0, 1, 1, 0, 0 },

{ 0, 0, 0, 0, 0, 0, 0, 1, 0, 0 }, { 0, 0, 1, 0, 1, 1, 0, 0, 0, 0 },

{ 1, 0, 0, 1, 0, 0, 1, 0, 1, 1 }, { 0, 0, 1, 0, 0, 0, 0, 0, 0, 1 },

{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0 }, { 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 },

{ 1, 1, 0, 0, 1, 1, 0, 0, 0, 0 }, { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0 },

{ 1, 0, 0, 0, 1, 1, 0, 0, 1, 0 }, { 1, 0, 0, 0, 1, 1, 0, 0, 0, 0 },

{ 1, 1, 0, 0, 0, 0, 0, 0, 1, 0 }, { 1, 0, 0, 0, 1, 0, 1, 0, 0, 0 },

{ 1, 0, 0, 0, 0, 1, 0, 1, 0, 0 }, { 1, 1, 0, 0, 0, 1, 0, 0, 0, 0 },

{ 1, 1, 0, 0, 1, 1, 0, 1, 0, 0 } };

public int[] FoodValue = { 31, 66, 55, 70, 34, 50, 106, 38, 62, 49, 55, 82,

33, 13, 118, 54, 83, 15, 56, 123, 32, 40, 52, 63, 18, 74, 49, 62,

64, 55, 70, 100 };

public void run() {

khoitao();

for (int i = 0; i < 100; i++) {

danhgia();

print();

luachon();

laighep();

dotbien();

}

}

int N = 100;

int[][] cathes = new int[N][];

Random rand = new Random();

private void khoitao() {

for (int i = 0; i < N; i++) {

cathes[i] = new int[this.Food.length];

for (int j = 0; j < cathes[i].length; j++)

cathes[i][j] = rand.nextInt(2);

}

}

int[] f = new int[N];

private void danhgia() {

// giaca

for (int i = 0; i < N; i++) {

f[i] = 0;

for (int j = 0; j < cathes[i].length; j++)

if (cathes[i][j] == 1)

f[i] += this.FoodValue[j];

// đinh duong

for (int d = 0; d < 10; d++) {

boolean ok = false;

for (int j = 0; j < cathes[i].length; j++)

if (cathes[i][j] == 1)

if (this.Food[j][d] == 1)

ok = true;

if (!ok)

f[i] = f[i] + 30;

}

}

}

private void luachon() {

int[] temp = f.clone();

Arrays.sort(temp);

int nguong = temp[N * 80 / 200];

for (int i = 0; i < N; i++) {

if (f[i] > nguong) {

cathes[i] = cathes[rand.nextInt(N)].clone();

}

}

}

private void laighep() {

for (int i = 0; i < N / 5; i++) {

int vo = rand.nextInt(N);

int chong = rand.nextInt(N);

for (int j = 0; j < this.Food.length; j++)

if (rand.nextInt(2) == 1) {

int temp = cathes[vo][j];

cathes[vo][j] = cathes[chong][j];

cathes[chong][j] = temp;

}

}

}

private void dotbien() {

int ct = rand.nextInt(N);

int index = rand.nextInt(this.Food.length);

cathes[ct][index] = 1 - cathes[ct][index];

}

public static void main(String[] args) {

(new Menu()).run();

}

private void print() {

int[] temp = f.clone();

Arrays.sort(temp);

for (int i = 0; i < N; i++)

if (f[i] == temp[0]) {

for (int j = 0; j < cathes[i].length; j++)

if (cathes[i][j] == 1)

System.out.print(this.FoodName[j] + ",");

break;

}

System.out.println("" + temp[0]);

}

}