我正在尝试确保在Android上的数学应用中不会重复生成的答案。这是我的代码： 如果我用这个数据初始化一个人物对象数组
private int answer = 0, operator = 0, operand1 = 0, operand2 = 0;
private Random random;
private int AnswerCounter = 0;
private int[] numberList {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30};
private int[] ans =new int[50];
private String[] operators = {"+", "-", "x", "/"};
以下是我用于随机化和双重检查重复答案的方法。 ans []似乎没有工作......
这可能是一个非常愚蠢的逻辑问题，但我一直在把头发拉到这里，但是无法解决这个问题。当我运行该程序时，答案仍然超过30，并且仍然有重复的答案。
感谢您寻找：）
private void chooseQuestion(){//if answer is repeated, operands and operators should be randomized again.
operator = random.nextInt(operators.length);
//choose operands
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
//checks for operators
if(operator==0){//ADD_OPERATOR
answer = operand1+operand2;
if(AnswerCounter==0){//first ans
while(answer>30){
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1+operand2;
}
}
else{//from the 2nd ans onwards
for (int x=0; x<(AnswerCounter);x++){
while((answer==ans[x])||(answer>30)){
//choose operands
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1+operand2;
}
}
}
ans[AnswerCounter] = answer;
AnswerCounter++;//increase so that the array num can increase
}
else if(operator==1){ //SUBTRACT_OPERATOR
answer = operand1-operand2;
if(AnswerCounter==0){//first ans
while((operand2>operand1)||answer>30){//no negative answer allowed, answer cannot be above 30
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1-operand2;
}
}
else{//from the 2nd ans onwards
for (int x=0; x<(AnswerCounter);x++){
while((operand2>operand1)||answer==ans[x]||(answer>30)){
//choose operands
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1+operand2;
}
}
}
answer = operand1-operand2;
ans[AnswerCounter] = answer;
AnswerCounter++;//increase so that the array num can increase
}
else if(operator==2){ //MULTIPLY_OPERATOR
/*
while(operand1>12||operand2>12){
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
}
//while(operand2>13){
//operand2 = random.nextInt(numberList.length);
//}
*/
answer = operand1*operand2;
if(AnswerCounter==0){//first ans
while(answer>30){
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1+operand2;
}
}
else{//from the 2nd ans onwards
for (int x=0; x<(AnswerCounter);x++){
while((operand1>12||operand2>12)||answer==ans[x]||(answer>30)){
//choose operands
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1*operand2;
}
}
}
answer = operand1*operand2;
ans[AnswerCounter] = answer;
AnswerCounter++;//increase so that the array num can increase
}
else if(operator==3){ //DIVIDE_OPERATOR
/*
//whole numbers only
while((((double)operand1/(double)operand2)%1 > 0)
|| (operand1==operand2)||(operand1==0)||(operand2==0)){
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
}
*/
//answer = operand1/operand2;// not sure if this is an error
if(AnswerCounter==0){//first ans
while((((double)operand1/(double)operand2)%1 > 0)||(operand1==operand2)||(operand1==0)||answer>30){
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1/operand2;
}
}
else{//from the 2nd ans onwards
for (int x=0; x<(AnswerCounter);x++){
while((((double)operand1/(double)operand2)%1 > 0) || (operand1==operand2)||(operand1==0)||answer==ans[x]||(answer>30)){
//choose operands
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1/operand2;
try {//||(operand2==0)
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1/operand2;
} catch(ArithmeticException ex) {
operand2+=1;
}
}
}
answer = operand1/operand2;
ans[AnswerCounter] = answer;
AnswerCounter++;//increase so that the array num can increase
}
}
答案 0 :(得分：0)
您可以使用不允许重复元素的HashSet来存储答案。因此，如果您尝试在集合中添加答案并返回false，则表示它是重复的。
答案 1 :(得分：0)
假设AnswerCounter为3，ans []包含[2,4,6]，然后下一个运算符为0，所以添加。此外，operand1为5，operand2为1.因此，代码表示：
for (int x=0; x<(AnswerCounter);x++){
while((answer==ans[x])||(answer>30)){
//choose operands
operand1 = random.nextInt(numberList.length);
operand2 = random.nextInt(numberList.length);
answer = operand1+operand2;
}
}
X = 0且1次传递OK，但接着是x == 2，条件失败，因为answer（6）== ans [x]因此必须选择另一个数字。也许这次它选择operand1和operand2为2.这个时间回答== 4，它不等于ans [x]，所以条件通过并且循环完成，所以ans []变为[2,4， 6,4]。
要解决这个问题，请按照以下几点思考：检查一个值是否重复是一个逻辑＆＃34; chunk＆＃34;或＆＃34;单位＆＃34;工作 - 例如。你可以有一个功能＆＃34; isNotDuplicate＆＃34;。你会如何安排你的代码，以便只从一个地方调用这个函数？