while 循环
int i = 0;
while(i < 10){
i++; //变量的值增加1
System.out.println(i); //输出变量的值
}
for循环
/* 建立一个Collection */
String[] strings = {"A", "B", "C", "D"};
Collection list = java.util.Arrays.asList(strings);
/* 开始遍历 */
for (Object str : list) {
System.out.println(str); /* 依次输出“A”、“B”、“C”、“D” */
}
或是
/* 建立一个数组 */
int[] integers = {1, 2, 3, 4};
/* 开始遍历 */
for (int j = 0; j < integers.length; j++) {
int i = integers[j];
System.out.println(i);
}
或是
/* 建立一个Collection */
String[] strings = {"A", "B", "C", "D"};
Collection stringList = java.util.Arrays.asList(strings);
/* 开始遍历 */
for (Iterator itr = stringList.iterator(); itr.hasNext();) {
Object str = itr.next();
System.out.println(str);
}
while
public static void main(String[] args){
int a=1,result=0;
do{
result+=a++;
}while(a<=100);
System.out.println(result);
}
if else
int a = 10;
if(a >= 0)
System.out.println(“a是正数”);
if( a % 2 == 0)
System.out.println(“a是偶数”);
switch
public static void test(int index) {
switch (index) {
case 1:
System.out.println(1);
case 2:
System.out.println(2);
case 3:
System.out.println(3);
default:
System.out.println("Default");
}
}