String to 32 bit Integer in Java, with default value than exception

Question

I have a string of signed integer value that could range from "+2147483650" to "-9638527412". I need to parse them to a 32-bit integer, such that, when the string value is above the integer capacity (2^31) it should return the nearest possible integer value. Using "Integer.parseInt" is giving out of bound exception.

Example:

input: "+2147483650"
output: "+2147483647"
input: ""-963852741258"
output: "-2147483648"

I tried to use existing functions, but I'm stuck here.

---

try{
    //num =Integer.valueOf(stringNumber);
    num =Integer.parseInt(stringNumber);
}catch(Exception e){
    num = -2147483648; // if stringNumber is negative
    num = +2147483647 // if stringNumber is positive
}
  

  

Answer 1

Since your value range is limited to "+2147483650" to "-9638527412", you can parse to long and check for overflow.

public static int parse(String stringNumber) {
    long value = Long.parseLong(stringNumber);
    return (value < Integer.MIN_VALUE ? Integer.MIN_VALUE :
            value > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) value);
}

Test

System.out.println(parse("+2147483650"));
System.out.println(parse("42"));
System.out.println(parse("-9638527412"));

Output

2147483647
42
-2147483648