方法1

package Demo04;

public class Demdohd01 {
//maina方法
public static void main(String[] args) {
//实际参数:实际传递给他的参数
int sum = add(1, 2);
System.out.println(sum);
test();
}
//加法
//形式参数，用来定义作用
public static int add(int a,int b){
return a+b;

}
// void的意思是空
public static void test(){
for (int i = 1; i <= 5; i++) {
for (int j = 5; j >= i; j--) {
System.out.print(" ");
}
for (int j = 1;j <=i;j++ ) {
System.out.print("");
}
for (int j = 5; j <= i; j++) {
System.out.print("");
}
System.out.println();

}
}
}

package Demo04;

public class Demo02 {
public static void main(String[] args) {
int max = max(5, 5,5);
System.out.println(max);
}
//比大小
public static double max(double num1,double num2) {
double result = 0;
if (num1num2) {
System.out.println("num1num2");
return 0;//终止方法
}
if (num1 > num2) {
result = num1;
}else {
result = num2;
}

return result;
}
public static int max(int num1,int num2,int num3) {
int result = 0;
if (num1num2) {
if (num2 == num3) {
System.out.println("num1num2");
System.out.println("num2==num3");
return 0;//终止方法
}
}
if (num1 > num2) {
result = num1;
}else {
result = num2;
}
if (num2 > num3){
}else {
result = num3;
}
return result;
}
}

package Demo04;

public class Demo3 {
public static void main(String[] args) {
max();
int sum = sun(20,10);
System.out.println(sum);
}
public static void max(){
for (int i = 1; i <= 9; i++) {
for (int j = 1; j <= i; j++) {
System.out.print(i+""+j+"="+(ij)+"\t");
}
System.out.println();
}
}
public static int sun(int a,int c){
int rug = 0;
if (ac){
System.out.println("ac");
return 0;
}
if (a>c){
rug = a;
} else {
rug = c;
}
return rug;
}
}