[英]How to loop through multiple input lines in Java
對於這個問題,我需要找到兩個點之間的距離給定兩個點的坐標和值p使用公式。 我讓程序適用於一個輸入行,但我希望用戶能夠輸入多行並讓程序循環通過它們。 例如:
1.0 1.0 2.0 2.0 1.0
1.0 1.0 2.0 2.0 2.0
可以是輸入,程序將讀取兩條線並給出兩個不同的距離值。 我想知道,如何讓掃描儀讀取多行輸入然后循環它們? 這是我現在的代碼:
public class Driver_lab3{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.print("Enter 2 coordinate points and a p value, as follows : x1 y1 x2 y2 p : ");
String coordinatestring = input.nextLine();
int stringposition = 0;
double x1 = 0.0;
double x2 = 0.0;
double y1 = 0.0;
double y2 = 0.0;
double p = 0.0;
String temp = "temp";
String spacecheck = "space";
String subb4decimal = "temp sub";
String subafterdecimal = "temp sub2";
int decimalpos = 0;
int spacepos = 0;
double distance;
if(Character.isDigit(coordinatestring.charAt(stringposition))){
decimalpos = coordinatestring.indexOf('.', stringposition);
subb4decimal = coordinatestring.substring(stringposition, decimalpos);
spacepos = coordinatestring.indexOf(' ', decimalpos);
subafterdecimal = coordinatestring.substring(decimalpos, spacepos);
temp = subb4decimal + subafterdecimal;
x1 = Double.parseDouble(temp);
stringposition = spacepos + 1;
decimalpos = coordinatestring.indexOf('.', stringposition);
subb4decimal = coordinatestring.substring(stringposition, decimalpos);
spacepos = coordinatestring.indexOf(' ', decimalpos);
subafterdecimal = coordinatestring.substring(decimalpos, spacepos);
temp = subb4decimal + subafterdecimal;
y1 = Double.parseDouble(temp);
stringposition = spacepos + 1;
decimalpos = coordinatestring.indexOf('.', stringposition);
subb4decimal = coordinatestring.substring(stringposition, decimalpos);
spacepos = coordinatestring.indexOf(' ', decimalpos);
subafterdecimal = coordinatestring.substring(decimalpos, spacepos);
temp = subb4decimal + subafterdecimal;
x2 = Double.parseDouble(temp);
stringposition = spacepos + 1;
decimalpos = coordinatestring.indexOf('.', stringposition);
subb4decimal = coordinatestring.substring(stringposition, decimalpos);
spacepos = coordinatestring.indexOf(' ', decimalpos);
subafterdecimal = coordinatestring.substring(decimalpos, spacepos);
temp = subb4decimal + subafterdecimal;
y2 = Double.parseDouble(temp);
stringposition = spacepos + 1;
decimalpos = coordinatestring.indexOf('.', stringposition);
subb4decimal = coordinatestring.substring(stringposition, decimalpos);
spacepos = coordinatestring.indexOf(' ', decimalpos);
subafterdecimal = coordinatestring.substring(decimalpos, spacepos);
temp = subb4decimal + subafterdecimal;
p = Double.parseDouble(temp);
stringposition = spacepos + 1;
distance = Math.pow(((Math.pow((Math.abs(x1-x2)),p)) + (Math.pow((Math.abs(y1-y2)),p))),(1.0/p));
System.out.println(distance);
System.out.println(x1);
System.out.println(x2);
System.out.println(y1);
System.out.println(y2);
System.out.println(p);
stringposition = 0;
}
}
}
我對java很新,還在學習,所以我很感激我能得到的任何幫助。 提前致謝。
首先你可以使用input.nextDouble()
來獲取double值,你可以使用try
catch
來處理錯誤的輸入,你可以使用for循環來迭代輸入
for (int i = 0; i < numOfInputs; i++){
try{
x1 = s.nextDouble();
y1 = s.nextDouble();
x2 = s.nextDouble();
y2 = s.nextDouble();
p = s.nextDouble();
} catch (InputMismatchException e) {
System.out.println("Incorrect input");
}
// your logic here
distance = Math.pow(((Math.pow((Math.abs(x1-x2)),p)) + (Math.pow((Math.abs(y1-y2)),p))),(1.0/p));
System.out.println(distance);
System.out.println(x1);
System.out.println(x2);
System.out.println(y1);
System.out.println(y2);
System.out.println(p);
}
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