table（制表符）:四个空格、缩进
xin+r:打开运行窗口
win+w：截屏
名字不能以数字开头，
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Ctrl+S 保存
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Ctrl+X 剪切
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*home 跳至行首
end 跳至末尾
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home 恩德扥、
public class For{
public static void main(String [] args){
// for(init;condition;update){
// }
// for (int i = 1; i <= 10;i++){
// System.out.println(i);
// }
// for(int i = 10;i >= 1 ;i--){
// System.out.println(i);
// }
// int total = 0;
// for(int i = 1;i<=100;i++){
// total += i;
// }
// System.out.println(total);
// for (int i = 1; i<100;i++){
// if(i%2==1)
// System.out.println(i);
// }
for (int i = 1; i<100;i+=2){
System.out.println(i);
}
}
}
public class While{
public static void main(String [] args){
// while(true){
// System.out.println("??");
// }
// int i = 1 ;
// while(i<=5){
// System.out.println("?");
// i++;
// }
// int i = 1;
// while (i<=10){
// System.out.println(i);
// i++;
// }
// int i = 10;
// while(i>=1){
// System.out.println(i);
// i--;
// }
int i = 1;
int total = 0;
while(i<=100){
total +=i;//total=total+ i;
System.out.println(total);
i++;//i自增;
}
}
shift
public class Switch{
public static void main (String [] args){
int a = 3;
switch(a){
case 1:
System.out.println("a的值是1");
break;
case 2:
System.out.println("a的值是2");
break;
default:
System.out.println("?");
}
int b =10;
switch(b){
case 5:
System.out.println("?");
break;
case 17:
System.out.println("z");
break;
default:
System.out.println("zz");
}
}
}
public class If{
public static void main (String [] args ){
//int hp = 100;
//if(hp<=0){
//System.out.println("菜");
//}
// if(hp<=0){
// System.out.println();
// }
//if(hp>0){
//System.out.println();
//
//if(hp>0){
// System.out.println("淦");
//}
//else{
// System.out.println("菜");
//}
/** int score = 80;
if(score>=0 && score <=100){
System.out.println("你这个弟弟");
}
else if (score>=101 && score <= 300){
System.out.println("还是弟弟");
}
else if (score>=301 && score <= 500){
System.out.println("还是弟弟");
}
else if (score>=501 && score <= 700){
System.out.println("还是弟弟");
}
*/
int a=9,b=20;
int max=a>b?a:b;
if(a>b){
max = a;
}
else{
max = b;
}
System.out.println(max);
int c= 100,d= 150;
int g=c>d?c:d;
if(c>d){
g = c;
}
else{
g = d;
}
System.out.println(g);
}
}
public class If{
public static void main (String [] args ){
int hp = 100;
//if(hp<=0){
//System.out.println("菜");
//}
// if(hp<=0){
// System.out.println();
// }
//if(hp>0){
//System.out.println();
//
//if(hp>0){
// System.out.println("淦");
//}
//else{
// System.out.println("菜");
//}
int score = 80;
if(score>=0 && score <=100){
System.out.println("你这个弟弟");
}
else if (score>=101 && score <= 300){
System.out.println("还是弟弟");
}
else if (score>=301 && score <= 500){
System.out.println("还是弟弟");
}
else if (score>=501 && score <= 700){
System.out.println("还是弟弟");
}
}
}
public class zz{
public static void main (String [] args){
int x = 5, y = 6,z;
z = ++x + y++;
System.out.println(z);//12
z = ++x + x++;
System.out.println(z);//12
x = ++x + x++;
System.out.println(x); //12
z = x > y ? ++x : y++;
System.out.println(z);//6 这里赋值的是y
}
}
wozaiganshenme
tab4空格
public class TernaryOperator{
public static void main (String [] args){
/**
int a = 5;
System.out.println(a>8?"干死黄旭东":"干死孙一峰");
int b = 2;
System.out.println(b>10?"老八":"奥利给");
int c = 15;
System.out.println(7>10?"c=11":"c=12");
*/
/** int a = 30, b =34, c = 300;
int max = a>b?a:b;
max = max>c?max:c;//通过赋值语句将右侧三元运算的最大值，赋值于max;
System.out.println(max);//输出max;
*/
int a = 1, b = 2;
boolean gan = ((a>b) && (a<10))
&&
b >100;//false true false//false;
System.out.println("爷晕了");
System.out.println(gan);
int 黄旭东 = 250;
int 孙一峰 = 249;
boolean 双狗 = ((黄旭东>孙一峰) |(黄旭东<孙一峰) );
System.out.println(双狗);
}
}
/*
*/
public class Logical{
public static void main (String [] args){
int age = 80;
/**boolean isAdult = age >= 18;//25 35;
boolean isZhong = age >= 25 && age <=35;//&& and;
//boolean isZhong = age >= 25 && age <=35;//&& and;两个条件要用&&连接;
System.out.println(isZhong);
System.out.println(isAdult);
*/
boolean isCannotPlay = age <=17 || age>=80;
int a = 8, b=3, c=9 ;
/**System.out.println(a>b && a>c);//true && false
System.out.println(a>b && a<c);//true && true
System.out.println(a<b && a>c);//false && false
System.out.println(a<b && a<c);//false && true
*/
/**System.out.println(a>b || a>c);//true
System.out.println(a<b || a<c);//true
System.out.println(a<b || a>c);//false
System.out.println(a<b || a<c);//true
*/
/**System.out.println(a>b ^ a>c);//true
System.out.println(a>b ^ a<c);//false
System.out.println(a<b ^ a>c);//false
System.out.println(a<b ^ a<c);//true
*/
System.out.println( !(a>b) );//false
System.out.println( !(a<b) );//true
}
}
/*
*/
public class Logical{
public static void main (String [] args){
int age = 80;
boolean isAdult = age >= 18;//25 35;
boolean isZhong = age >= 25 && age <=35;//&& and;
//boolean isZhong = age >= 25 && age <=35;//&& and;两个条件要用&&连接;
System.out.println(isZhong);
System.out.println(isAdult);
}
}
public class CompareOperator{
public static void main (String [] args){
int a = 10;
int b = 2;
System.out.println(a<b);//false
System.out.println(a<=b);//false
System.out.println(a>b);//true
System.out.println(a>=b);//true
System.out.println(a==b);//false
System.out.println(a!=b);//true
System.out.println('a'<'b');//true
System.out.println('a');//a
System.out.println(a=b);//2
int c = 'a';
System.out.println(c);//a=97;
}
}
public class Assignment{
public static void main (String [] args){
int a = 3;
int x,y,z;
x = y = z = 4;
a += 4;//a = a + 4;7
System.out.println(a);
a -= 5;//2
System.out.println(a);
a *= 4;//8
System.out.println(a);
a /= 2;//4
System.out.println(a);
a %= 7;//4
System.out.println(a);
}
}
public class ZiZeng{
public static void main (String [] args){
int a=9;
int b =5;
//++a;
//--b;
int res1 = a++ + 1;
int res2 = ++b + 2;
int res3 = --a;
int res4 = --b;
System.out.println(a);
System.out.println(b);
System.out.println(res1);
System.out.println(res2);
System.out.println(res3);
System.out.println(res4);
}
}
硬是用变量打数字
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