java for switch_java中switch结构和 while for循环的用法

6.2 switch结构：

变量可以是：variable can be:(mark: tried, can not be long)

char/int/short/byte(java1.7 就可以用String来switch了)

public class Test{

public static void main(String[] args){

double d1=0.0, d2=0.0;

d1 = 11;

d2 = 22;

char o = '+';

switch(o){

case '+':

System.out.println(d1+d2);

break;

case '-':

System.out.println(d1-d2);

break;

case '*':

System.out.println(d1*d2);

break;

case '/':

System.out.println(d1/d2);

}

}

}

6.3 循环

6.3.1 while 循环

public class Test{

public static void main(String[] args){

int lim = 5;

int sum = 0;

int i = 1;

while(i<=lim){

sum =sum + i;

i++;

}

System.out.println("sum = " + sum);

int j = 1;

while(j<=4){

System.out.println("j=" + j);

j++;

}

System.out.println(j);

}

}