Java：將字符串解析爲int並計算總和

Question

首先，我想先說我不只是在尋找某人給我這個問題的答案，我是一名初學者程序員，我只是想學習儘可能多。對我的代碼的批評以及對正確方向的友好推動將非常感謝！真正讓我困惑的是我的stringParser方法。我使用這種方法遍歷字符串，挑出數字並將它們存儲在一個新字符串中進行解析。令我困惑的是如何將這些數字加在一起？這裏是代碼：

public static int stringParser(String parsee,int parsed) 
{ 
    int indexOfString = parsee.indexOf("=");   //Searches for an = sign since there has to be one 
    String parsee2 = ""; 
    int [] newArray; 
    String subStringParse = parsee.substring(0,indexOfString);  //Substring made to divide string, this one is from 0 index to 1st occurence of = 
    for(int i = 0;i<subStringParse.length();i++) 
    { 
     if(Character.isDigit(subStringParse.charAt(i)))  //if the value is a number it is stored in a new string then parsed. 
     { 
      parsee2+= subStringParse.charAt(i); 
      parsed = Integer.parseInt(parsee2); 

     }   
    }   return parsed; 

} 
public static int sumInts(int a,int storedSums) 
{ 
    //a = new int[20]; 
    for(int i=0;i<a;i++) //loops through parsed string from stringParser 
    { 
     storedSums += a;   //creates a new value calculating sum 
    } 
    return storedSums; 
} 

Answer 1

根據我的猜測，你想解析這樣的`12 + 34 ='。

如果我是對的，那麼你的循環是完全錯誤的。它將只返回34作爲整數值。你可以調試你的代碼。

我建議你這樣的事情：

int index = 0; 
for(int i = 0;i<subStringParse.length();i++) 
{ 
    if(Character.isDigit(subStringParse.charAt(i)))  //if the value is a number it is stored in a new string then parsed. 
    { 
     parsee2+= subStringParse.charAt(i); 
     parsed = Integer.parseInt(parsee2); 
    }   
    newArray[index++] = parsed; //make sure you initialize newArray. 
}  
return newArray; 

Answer 2

嘗試，

String parsee = "12+13 = 34+45 = 45+-45"; 
int value = 0; 
String parsed = ""; 
for(String exp : parsee.split("=")){    
    for(String val : exp.trim().split("\\+")){ 
     value+=Integer.parseInt(val); 
    } 
    parsed+=" SUM = "+value; 
    value = 0; 
} 
System.out.println(parsed); 

輸出

SUM = 25 SUM = 79 SUM = 0