Sum of string array elements in java

Question

I have a String array which have both integers as well as strings. I want to calculate the sum of all integer array elements.

class Array{
String container[] = {"Joe","12","Chandler","15","67","Rajat",'a'};
int sum;
for(String element:container){
    int num = Integer.parseInt(element); 
    sum += num;
}
void print(){
    System.out.print(sum);
}
}
class ArrayDemo{
public static void main(String args[]){
    Array a = new Array();
    a.print();
}
}

But the code int num = Integer.parseInt(element) gives NumberFormatException because Joe,Chandler,Rajat are not integers. So, how to resolve this problem. The answer should be the sum of 12+15+67=94

Thanks in advance

No, it is not compiling but why because I wrote code directly in the class? — user3520629, Jul 26 '16 at 08:43
yes that is a reason. That for loop will give error and also the last element of your array is not a string that is also an error. — Saif, Jul 26 '16 at 08:52

score 3 · Accepted Answer · answered Jul 26 '16 at 08:30

3

Include your parse inside a try catch block

for(String element:container){
  try {
    int num = Integer.parseInt(element); 
    sum += num;
  catch (NumberFormatException nfe){
    System.out.println ("Element " + element + " in the array is not an integer");
  }
}

answered Jul 26 '16 at 08:30

SCouto

7,808
5
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You forgot to close try block else your code is working and it solved my problem. – user3520629 Jul 26 '16 at 08:52

Adnan Isajbegovic · Answer 2 · 2016-07-26T08:35:40.913

-1

you need to handle that exception:

class Array{
String container = {"Joe","12","Chandler","15","67","Rajat",'a'};
int sum;
for(String element:container){
    try {
        int num = Integer.parseInt(element); 
    catch(Exception e) {
        continue;
    }
    sum += num;
}
void print(){
    System.out.print(sum);
}
}
class ArrayDemo{
public static void main(String args[]){
    Array a = new Array();
    a.print();
}
}

Use try-catch for this. If exception happens, just continue to next iteration in for loop. When its a number, it will be added to sum.

Another approach is to check each char in string if its a number. This is a quite long code, so use one existing (you will need to include Apache Commons library):

NumberUtils.isNumber(String str)

or

StringUtils.isNumeric(String str)

When this gives you true, add it to sum.

edited Jul 26 '16 at 08:35

answered Jul 26 '16 at 08:29

Adnan Isajbegovic

2,227
17
27

2

This is incredibly bad practice: `catch(Exception e) { continue; }` – Idos Jul 26 '16 at 08:30
Why would it be a bad practice? – Adnan Isajbegovic Jul 26 '16 at 08:32
more or less [this](http://stackoverflow.com/questions/2416316/why-is-the-catchexception-almost-always-a-bad-idea) – Idos Jul 26 '16 at 08:34
As it says, you need to handle all exceptions... This does it... – Adnan Isajbegovic Jul 26 '16 at 08:38

Sum of string array elements in java

2 Answers2