Getting String and return the same string with " " before every"-"-CodePudding

I get a String and I need to return with " " before every "-"in it for example for the String= "5x^6 3x-8x^2-8x^3" it should return:5x^6 3x -8x^2 -8x^3

        String p="-5.0x^4-1.0x^3-3.0x^2-2.0"
        String temp=p;
        for(int i = 1;i<p.length();i  ) {
            int start=0;
            if(p.charAt(i)=='-') {
                temp =temp.substring(start,i);
                temp =" ";
                temp =p.substring(i 1,p.length());//here it over writes
                start=i;
            }
        }

it switches the "-" with " " the return: -5.0x^4 1.0x^3 3.0x^2 2.0

CodePudding user response：

Instead of concatentating substrings, I would use a StringBuilder. Iterate the contents. On - insert a . Like,

String p = "5x^6 3x-8x^2-8x^3";
StringBuilder sb = new StringBuilder(p);
for (int i = 0; i < sb.length(); i  ) {
    if (sb.charAt(i) == '-') {
        sb.insert(i, ' ');
        i  ;
    }
}
p = sb.toString();

Results in (as requested)

5x^6 3x -8x^2 -8x^3