java-for循环

简单的for 循环，可以初始化变量，检查条件和增加、减少变量的值。

语法：

for (initialization; condition; incr/decr){
       //code通被executed
}

实例：
package day02;

public class Test12 {

    /**
     * @param args
     * @author bindu
     */
    public static void main(String[] args) {

        for (int i = 1; i <= 10; i++) {
            System.out.println(i);
        }
    }

}

for-each 循环：

package day02;

public class Test12 {

    /**
     * @param args
     * @author bindu
     */
    public static void main(String[] args) {
        int attr[] = {12,22,33,34,56,66,78};
        for (int i: attr){
            System.out.println(i);
        }
    }

}

标记for 循环：

package day02;

public class Test12 {

    /**
     * @param args
     * @author bindu
     */
    public static void main(String[] args) {
        aa: for(int i =1;i<=3;i++){
            bb:for(int j = 1;j<=3;j++){
                if (i ==2&& j==2){
                    break aa;
                }
                System.out.println(i +" "+j);
            }
        }
    }

}

无限for循环：

package day02;

public class Test12 {

    /**
     * @param args
     * @author bindu
     */
    public static void main(String[] args) {
        for (;;){
            System.out.println("这就是死循环啊！");
        }
    }

}

 

求1！+2！+3！+...10!的和：

package homework;

public class Test10 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum =0;
        int times =1;
        for(int i =1;i<=10;i++){
            times*=i;
            sum+=times;
            
        }
        System.out.println("1!+2!+....10!="+sum);

    }

}

打印菱形：

package homework;

public class Test11 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // 打印菱形
        
        int ceng = 5;
        for (int i = 0; i < ceng; i++) {
            for (int j = 0; j < ceng-i-1; j++) {
                System.out.print(" ");
            }
            for (int k = 0; k < 2*i+1; k++) {
                System.out.print("*");
            }
            System.out.println("");
        }
        for (int i = 0; i < ceng-1; i++) {
            for (int j = 0; j < i+1; j++) {
                System.out.print(" ");
            }
            for (int k = 0; k < 2*(ceng-i-2)+1; k++) {
                System.out.print("*");
            }
            System.out.println("");
        }
    }

}