java无法理解为什么我的程序不打印数组的内容
我正在尝试用java创建24小时游戏来练习。24游戏是一种算术游戏,其目标是找到一种方法来处理四个整数,从而最终结果为24。可以使用任何数字顺序的加法、减法、乘法或除法使1到9的四位数运算等于24
规则很简单:每个数字只需使用一次,并且只需从用户处读取4个数字,就可以找到一个方程式,得到24
我的问题是程序完成后我没有收到任何输出。问题可能出在append(String-equation)方法中,该方法用于防止重复答案并将正确的方程式添加到ans数组中。或者它可能在别的地方。我一辈子都搞不懂
编辑代码:
public class TwentyFourGame {
String [] ans = new String[20];
boolean [] used = new boolean[20];
int count = 0;
int value = 0;
public void Solve(double w, double x, double y, double z){
double [] nums = {w,x,y,z};
double eHold=0, fHold=0;
//Replaces null array elements with empty string to avoid NPE
for(int d=0; d<ans.length;d++){
ans[d] = "";
}
for (int a=0;a< 4; a++){
for (int b=0;b< 3; b++){
for (int c=0;c<2; c++){
fHold = nums[2]+nums[3];
if (((nums[0]/nums[1])*fHold)==24)
append (nums[0]+" / "+nums[1]+" * ("+nums[2]+" + "+nums[3]+")" + " = 24");
else if (((nums[0]/nums[1])-fHold)==24)
append (nums[0]+" / "+nums[1]+" - ("+nums[2]+" + "+nums[3]+")" + " = 24");
else if (((nums[0]*nums[1])-fHold)==24)
append (nums[0]+" * "+nums[1]+" - ("+nums[2]+" + "+nums[3]+")" + " = 24");
else if (((nums[0]*nums[1])/fHold)==24)
append (nums[0]+" * "+nums[1]+" / ("+nums[2]+" + "+nums[3]+")" + " = 24");
else if (((nums[0]-nums[1])*fHold)==24)
append (nums[0]+" - "+nums[1]+" * ("+nums[2]+" + "+nums[3]+")" + " = 24");
else if (((nums[0]-nums[1])/fHold)==24)
append (nums[0]+" - "+nums[1]+" / ("+nums[2]+" + "+nums[3]+")" + " = 24");
else value++;
fHold=nums[2]-nums[3];
if (((nums[0]/nums[1])*fHold)==24)
append (nums[0]+" / "+nums[1]+" * ("+nums[2]+" - "+nums[3]+")" + " = 24");
else if (((nums[0]/nums[1])+fHold)==24)
append (nums[0]+" / "+nums[1]+" + ("+nums[2]+" - "+nums[3]+")" + " = 24");
else if (((nums[0]*nums[1])+fHold)==24)
append (nums[0]+" * "+nums[1]+" + ("+nums[2]+" - "+nums[3]+")" + " = 24");
else if (((nums[0]*nums[1])/fHold)==24)
append (nums[0]+" * "+nums[1]+" / ("+nums[2]+" - "+nums[3]+")" + " = 24");
else if (((nums[0]+nums[1])*fHold)==24)
append (nums[0]+" + "+nums[1]+" * ("+nums[2]+" - "+nums[3]+")" + " = 24");
else if (((nums[0]+nums[1])/fHold)==24)
append (nums[0]+" + "+nums[1]+" / ("+nums[2]+" - "+nums[3]+")" + " = 24");
else value++;
fHold=nums[2]*nums[3];
if (((nums[0]/nums[1])-fHold)==24)
append (nums[0]+" / "+nums[1]+" * ("+nums[2]+" * "+nums[3]+")" + " = 24");
else if (((nums[0]/nums[1])+fHold)==24)
append (nums[0]+" / "+nums[1]+" + ("+nums[2]+" * "+nums[3]+")" + " = 24");
else if (((nums[0]-nums[1])+fHold)==24)
append (nums[0]+" - "+nums[1]+" + ("+nums[2]+" * "+nums[3]+")" + " = 24");
else if (((nums[0]-nums[1])/fHold)==24)
append (nums[0]+" - "+nums[1]+" / ("+nums[2]+" * "+nums[3]+")" + " = 24");
else if (((nums[0]+nums[1])-fHold)==24)
append (nums[0]+" + "+nums[1]+" - ("+nums[2]+" * "+nums[3]+")" + " = 24");
else if (((nums[0]+nums[1])/fHold)==24)
append (nums[0]+" + "+nums[1]+" / ("+nums[2]+" * "+nums[3]+")" + " = 24");
else value++;
fHold=nums[2]/nums[3];
if (((nums[0]-nums[1])*fHold)==24)
append (nums[0]+" - "+nums[1]+" * ("+nums[2]+" / "+nums[3]+")" + " = 24");
else if (((nums[0]-nums[1])+fHold)==24)
append (nums[0]+" - "+nums[1]+" + ("+nums[2]+" / "+nums[3]+")" + " = 24");
else if (((nums[0]*nums[1])+fHold)==24)
append (nums[0]+" * "+nums[1]+" + ("+nums[2]+" / "+nums[3]+")" + " = 24");
else if (((nums[0]*nums[1])-fHold)==24)
append (nums[0]+" * "+nums[1]+" - ("+nums[2]+" / "+nums[3]+")" + " = 24");
else if (((nums[0]+nums[1])*fHold)==24)
append (nums[0]+" + "+nums[1]+" * ("+nums[2]+" / "+nums[3]+")" + " = 24");
else if (((nums[0]+nums[1])-fHold)==24)
append (nums[0]+" + "+nums[1]+" - ("+nums[2]+" / "+nums[3]+")" + " = 24");
else value++;
fHold=nums[1]*nums[2];
if (((nums[0]-fHold)/nums[3])==24)
append (nums[0]+" - ("+nums[1]+" * "+nums[2]+") / "+nums[3] + " = 24");
else if (((nums[0]-fHold)+nums[3])==24)
append (nums[0]+" - ("+nums[1]+" * "+nums[2]+") + "+nums[3] + " = 24");
else if (((nums[0]/fHold)+nums[3])==24)
append (nums[0]+" / ("+nums[1]+" * "+nums[2]+") + "+nums[3] + " = 24");
else if (((nums[0]/fHold)-nums[3])==24)
append (nums[0]+" / ("+nums[1]+" * "+nums[2]+") - "+nums[3] + " = 24");
else if (((nums[0]+fHold)/nums[3])==24)
append (nums[0]+" + ("+nums[1]+" * "+nums[2]+") / "+nums[3] + " = 24");
else if (((nums[0]+fHold)-nums[3])==24)
append (nums[0]+" + ("+nums[1]+" * "+nums[2]+") - "+nums[3] + " = 24");
else value++;
fHold=nums[1]-nums[2];
if (((nums[0]*fHold)/nums[3])==24)
append (nums[0]+" * ("+nums[1]+" - "+nums[2]+") / "+nums[3] + " = 24");
else if (((nums[0]*fHold)+nums[3])==24)
append (nums[0]+" * ("+nums[1]+" - "+nums[2]+") + "+nums[3] + " = 24");
else if (((nums[0]/fHold)+nums[3])==24)
append (nums[0]+" / ("+nums[1]+" - "+nums[2]+") + "+nums[3] + " = 24");
else if (((nums[0]/fHold)*nums[3])==24)
append (nums[0]+" / ("+nums[1]+" - "+nums[2]+") * "+nums[3] + " = 24");
else value++;
fHold=nums[1]/nums[2];
if (((nums[0]-fHold)*nums[3])==24)
append (nums[0]+" - ("+nums[1]+" / "+nums[2]+") * "+nums[3] + " = 24");
else if (((nums[0]-fHold)+nums[3])==24)
append (nums[0]+" - ("+nums[1]+" / "+nums[2]+") + "+nums[3] + " = 24");
else if (((nums[0]*fHold)+nums[3])==24)
append (nums[0]+" * ("+nums[1]+" / "+nums[2]+") + "+nums[3] + " = 24");
else if (((nums[0]*fHold)-nums[3])==24)
append (nums[0]+" * ("+nums[1]+" / "+nums[2]+") - "+nums[3] + " = 24");
else if (((nums[0]+fHold)*nums[3])==24)
append (nums[0]+" + ("+nums[1]+" / "+nums[2]+") * "+nums[3] + " = 24");
else if (((nums[0]+fHold)-nums[3])==24)
append (nums[0]+" + ("+nums[1]+" / "+nums[2]+") - "+nums[3] + " = 24");
else value++;
fHold=nums[1]+nums[2];
if (((nums[0]*fHold)/nums[3])==24)
append (nums[0]+" * ("+nums[1]+" + "+nums[2]+") / "+nums[3] + " = 24");
else if (((nums[0]*fHold)-nums[3])==24)
append (nums[0]+" * ("+nums[1]+" + "+nums[2]+") - "+nums[3] + " = 24");
else if (((nums[0]/fHold)-nums[3])==24)
append (nums[0]+" / ("+nums[1]+" + "+nums[2]+") - "+nums[3] + " = 24");
else if (((nums[0]/fHold)*nums[3])==24)
append (nums[0]+" / ("+nums[1]+" + "+nums[2]+") * "+nums[3] + " = 24");
else value++;
if (value == 192){
append("There is no solution for this set of numbers");
this.count ++;
}
// 0=a 1=b 2=c 3=d
eHold=nums[2];
nums[2]=nums[3];
nums[3]=eHold;
}
eHold=nums[1];
nums[1]=nums[2];
nums[2]=nums[3];
nums[3]=eHold;
}
eHold=nums[0];
nums[0]=nums[1];
nums[1]=nums[2];
nums[2]=nums[3];
nums[3]=eHold;
for (int j=0; j<ans.length;j++){
if (ans[j] != "")
System.out.println(ans[j]);
}
}
}
//Method used to check if there are duplicates in the array of equations
public void append(String equation){
String text = equation;
for (int e=0;e<used.length;e++){
if (used[e]==false){
ans[e] = text;
used[e] = true;
break;
}
}
//Check if elements in the array are the same
for (int c=0;c<ans.length;c++){
for (int d = 0; d < ans.length; d++) {
//if elements are the same do nothing
if (ans[c].equals(ans[d])){
ans[d] = "";
}
}
}
}
public static void main(String[]args){
java.util.Scanner input = new java.util.Scanner(System.in);
System.out.println("Enter 4 numbers between 1 - 9");
double w,x,y,z;
TwentyFourGame Player1 = new TwentyFourGame();
w = input.nextDouble();
x = input.nextDouble();
y = input.nextDouble();
z = input.nextDouble();
input.close();
Player1.Solve(w,x,y,z);
}
}
# 1 楼答案
我怀疑你的逻辑是错误的,这就是为什么你从来没有使用
append(String)
方法。{cd2}如果你不期待,你会看到此外,一旦你点击了
append
方法(尝试1,1,3,7),当你尝试计算ans[c].equals(ans[d])
时,你会得到一个NullPointerException
,因为ans[c]
是空的# 2 楼答案
您不会将任何结果打印到控制台中。试着找到所有的系统。出来println(…)声明