java基础题

1.需求:根据用户定义的数值不同,打印对应的星期英文class Text01 {public static void main(String[] args) {int num = 3;if(num==1)System.out.println("num="+num+":Monday");else if(num==2)System.out.println("num="+num+":Tuesday");else if(num==3)System.out.println("num="+num+":Wednesday");else if(num==4)System.out.println("num="+num+":Thursday");else if(num==5)System.out.println("num="+num+":Friday");else if(num==6)System.out.println("num="+num+":Saturday");else if(num==7)System.out.println("num="+num+":Sunday");elseSystem.out.println("num="+num+":星期不存在");}}2.需求:根据用户指定的月份,打印该月份所属的季节(两种方式:if和switch)  定义:3,4,5  春季   6,7,8  夏季    9,10,11  秋季   12,1,2   冬季class Text02{public static void main(String[] args){int x = 5;if(x==3 || x==4 || x==5 )System.out.println(x+":春季");else if(x==6 || x==7 || x==8 )System.out.println(x+":夏季");else if(x==9 || x==10 || x==11 )System.out.println(x+":秋季");else if(x==12 || x==1 || x==2 )System.out.println(x+":冬季");elseSystem.out.println(x+":季节不存在");}}3.需求:获取1-10的和,并打印class Text03{public static void main(String[] args){int sum = 0;for(int x = 1; x<=10; x++){sum+=x;}System.out.println("sum="+sum);}}4.需求:1-100之间,7的倍数的个数,并打印.class Text04{public static void main(String[] args){int count=0;for(int x = 1; x<=100; x++){if(x%7==0){System.out.println("x="+x);count++;}}System.out.println("count="+count);}}5.需求:定义一个功能,完成两个整数和的运算,并将结果返回给调用者class Text05{public static void main(String[] args){int add = getAdd(3,9);System.out.println("add="+add);}public static int getAdd(int x,int y){return x+y;}}6.需求:定义一个功能,判断两个整数是否相同.class Text06{public static void main(String[] args){boolean b1=compare(2,3);System.out.println("b1="+b1);}public static boolean compare(int a,int b){//return a==b;if(a==b)return true;elsereturn false;}}7.需求:定义功能,对两个数进行比较,获取较大的数.class Text07{public static void main(String[] args){int max = getMax(5,9);System.out.println("max="+max);}public static int getMax(int m, int n){if(m>n)return m;elsereturn n;//return m>n?m:n;}}8.需求:定义功能,用于打印矩形.class Text08{public static void main(String[] args){print(5,6);        printLine();print(12,12);        printLine();}public static void print(int row, int col){for(int x=0; x<row; x++){for(int y=0; y<col; y++){System.out.print("$");}System.out.println();}}public static void printLine(){System.out.println("----------------------");}}9.需求:定义功能,用于打印乘法表.class Text09{public static void main(String[] args){print(9);}public static void print(int num){for(int x=1; x<=num; x++){for(int y=1; y<=x; y++){System.out.print(y+"*"+x+"="+y*x+"\t");}System.out.println();}}}10.需求:定义一个功能,用于打印数组中的元素,元素间用逗号隔开.class Text10{public static void main(String[] args){int[] arr ={1,3,5,7,9};printArray(arr);}public static void printArray(int[] arr){System.out.print("[");for(int x=0; x<arr.length; x++){if(x!=(arr.length-1))System.out.print(arr[x]+", ");elseSystem.out.print(arr[x]+"]");}}}11.需求:数组最大值,最小值,选择排序,冒泡排序,数组的折半查找.class Text11{public static void main(String[] args){int[] arr={2,9,1,12,8,34,10};int max =getMax(arr);System.out.println("max="+max);int min =getMin(arr);System.out.println("min="+min);printArray(arr);selectSort(arr);printArray(arr);        printArray(arr);bubbleSort(arr);printArray(arr);int index =halfSearch(arr,12);System.out.println("index="+index);}//数组的最大值public static int getMax(int[] arr){int max=arr[0];for(int x=1; x<arr.length; x++){if(arr[x]>max)max=arr[x];}return max;}//数组的最小值public static int getMin(int[] arr){int min=arr[0];for(int x=1; x<arr.length; x++){if(arr[x]<min)min=arr[x];}return min;}//选择排序public static void selectSort(int[] arr){for(int x=0; x<arr.length-1; x++){for(int y=x+1; y<arr.length; y++){if(arr[x]>arr[y]){swap(arr,x,y);}}}}//冒泡排序public static void bubbleSort(int[] arr){for(int x=0; x<arr.length-1; x++){for(int y=0;y<arr.length-x-1;y++){if(arr[y]>arr[y+1]){swap(arr,y,y+1);}}}}//位置置换public static void swap(int[] arr,int a, int b){int temp=arr[a];  arr[a]=arr[b];  arr[b]=temp;}//打印数组    public static void printArray(int[] arr){System.out.print("[");for(int x=0; x<arr.length; x++){if(x!=(arr.length-1))System.out.print(arr[x]+", ");elseSystem.out.println(arr[x]+"]");}}//折半查找(数组必须是有序的)public static int halfSearch(int[] arr,int key){int min,max,mid;min = 0;max = arr.length-1;mid = (min+max)/2;while(arr[mid]!=key){if(key>arr[mid])min = mid+1;else if(key<arr[mid])max = mid-1;mid = (min+max)>>1;if(min>max)return -1;}return mid;}}