方法及递归

方法

package method;*//比大小

public class Dome1 {
    public static void main(String[] args){
        int sub = sub(60,60);
        System.out.println(sub);

    }

    public static int sub(int num1,int num2){
        int result = 0;
        if (num1==num2){
            System.out.println("chen");
            return 0;//终止方法

        }
        if (num1<num2){
            result = num2;


        }else
            result = num1;
        return result;
    }







}

方法的重载

package method;

public class dome2 {
    public static void main(String[] args) {
        int sub = sub(10,20);
        





    }

    public static int sub(int a,int b){
        int asc = a + b;
        System.out.println(a + b);


        return asc;
    }






}

package method;

public class Dome1 {
    public static void main(String[] args){
        int sub = sub(60,60,30);//方法名称必须相同
        System.out.println(sub);

    }

    public static int sub(int num1,int num2,int num3){//参数列表必须不同（个数不同，类型不同，参数列表顺序不同）
        int result = 0;
        if (num1==num2){
            System.out.println("chen");
            return 0;//终止方法

        }
        if (num1<num2){
            result = num2;


        }else
            result = num1;
        return result;
    }







}

递归

递归头；什么时候不调用自身方法。如果没有头，将陷入死循环调用直到规定值然后再返回

递归体；什么时候需要调用自身方法

package method;

public class Dome4 {
    public static void main(String[] args) {
        System.out.println(a(4));
    }
    public static int a(int s){
        if (s==1){
            return 1;
        }else{
            return s*a(s-1);//24   4*3*2*1
        }
    }
}
package method;

public class Dome5 {
    public static void main(String[] args) {
        double sub=sub((double) 5, '/', (double) 2);
        System.out.println(sub);
    }
    public static double sub(double num1, char op, double num2) {
        int result=0;
        if (op == '+') {
            return num1 + num2;
        } else if (op == '-') {
            return num1 - num2;
        } else if (op == '*') {
            return num1 * num2;
        } else if (op == '/') {
            return num1 / num2;


        }
        return result;


    }
}
package method;

public class Dome5 {
    public static void main(String[] args) {
        double sub=sub((double) 5, '/', (double) 2);
        System.out.println(sub);
    }
    public static double sub(double num1, char op, double num2) {
        int result=0;
        if (op == '+') {
            return num1 + num2;
        } else if (op == '-') {
            return num1 - num2;
        } else if (op == '*') {
            return num1 * num2;
        } else if (op == '/') {
            return num1 / num2;


        }
        return result;


    }
}

package method;

public class Dome5 {
public static void main(String[] args) {
double sub=sub((double) 520, '', (double) 2);
System.out.println(sub);
}
public static double sub(double num1, char op, double num2) {
int result=0;
if (op == '+') {
return num1 + num2;
} else if (op == '-') {
return num1 - num2;
} else if (op == '') {
return num1 * num2;
} else if (op == '/') {
return num1 / num2;

    }
    return result;


}

}
package method;

public class Dome5 {
public static void main(String[] args) {
double sub=sub((double) 520, '', (double) 2);
System.out.println(sub);
}
public static double sub(double num1, char op, double num2) {
int result=0;
if (op == '+') {
return num1 + num2;
} else if (op == '-') {
return num1 - num2;
} else if (op == '') {
return num1 * num2;
} else if (op == '/') {
return num1 / num2;

    }
    return result;


}

}