Cannot find index of a character in java string

Question

I found a very strange problem in my java program. I want find indices of all pipe in my string and save them into 5 variables, but result is not right. Here is my program:

public class forTest {
    public static void main(String[] args){
        String tmp = "A|B|C|D|E|F|";
        int count = 0;
        int start = 0;
        int start1 = 0;
        int start2 = 0;
        int start3 = 0;
        int start4 = 0;
        for(int i = 0; i < tmp.length(); i++){
            if(tmp.substring(i, i+1).equals("|")){
                count = count + 1;
                System.out.println(i);
            }
            if(count == 1){
                start = i;
            }
            if(count == 2){
                start1 = i;
            }
            if(count == 3){
                start2 = i;
            }
            if(count == 4){
                start3 = i;
            }
            if(count == 5){
                start4 = i;
            }
        }
        System.out.println(start + "|" +start1 + "|" +start2
                                 + "|" +start3 + "|" +start4);
    }

Output:

Result is 1

1 3 5 7 9 11

2|4|6|8|10

Answer 1

As you iterate, the first | will increment count to 1 , and set start = 1 , but on next iteration when you're positioned on the B , the count is still 1, and start is updated to 2 .

Debugging with a breakpoint on start = i; would have let you see this for yourself!

Solution: Move all the if statements inside the first one.

Also, tmp.substring(i, i+1).equals("|") should be tmp.charAt(i) == '|' , and use else if .

for (int i = 0; i < tmp.length(); i++) {
    if (tmp.charAt(i) == '|') {
        count = count + 1;
        System.out.println(i);
        if (count == 1) {
            start = i;
        } else if (count == 2) {
            start1 = i;
        } else if (count == 3) {
            start2 = i;
        } else if (count == 4) {
            start3 = i;
        } else if (count == 5) {
            start4 = i;
        }
    }
}

---

Alternate solutions

A shorter piece of code to get the same result can be done using a regular expression:

String tmp = "A|B|C|D|E|F|";
String regex = "(\\|).*?(\\|).*?(\\|).*?(\\|).*?(\\|)";
Matcher m = Pattern.compile(regex).matcher(tmp);
if (m.find()) {
    int start  = m.start(1);
    int start1 = m.start(2);
    int start2 = m.start(3);
    int start3 = m.start(4);
    int start4 = m.start(5);
    System.out.println(start + "|" +start1 + "|" +start2 + "|" +start3 + "|" +start4);
}

Or if you don't like that, you could use an array:

String tmp = "A|B|C|D|E|F|";
int count = 0;
int[] start = new int[5];
for (int i = 0; i < tmp.length(); i++)
    if (tmp.charAt(i) == '|' && count < start.length)
        start[count++] = i;
System.out.println(start[0] + "|" +start[1] + "|" +start[2] + "|" +start[3] + "|" +start[4]);

Output (from both)

1|3|5|7|9