Remove Leading Zeros From String in Java

Given a string of digits, remove leading zeros from it.

Examples:

Input : 00000123569
Output : 123569

Input : 000012356090
Output : 12356090

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

We use StringBuffer class as Strings are immutable.

1) Count leading zeros.
2) Use StringBuffer replace function to remove characters equal to above count.

// Java program to remove leading/preceding zeros 
// from a given string 
import java.util.Arrays; 
import java.util.List; 
  
/* Name of the class to remove leading/preceding zeros */
class RemoveZero 
{ 
    public static String removeZero(String str) 
    { 
        // Count leading zeros 
        int i = 0; 
        while (i < str.length() && str.charAt(i) == '0') 
            i++; 
  
        // Convert str into StringBuffer as Strings 
        // are immutable. 
        StringBuffer sb = new StringBuffer(str); 
  
        // The  StringBuffer replace function removes 
        // i characters from given index (0 here) 
        sb.replace(0, i, ""); 
  
        return sb.toString();  // return in String 
    } 
  
    // Driver code 
    public static void main (String[] args) 
    { 
        String str = "00000123569"; 
        str = removeZero(str); 
        System.out.println(str); 
    } 
} 

Output:

Remove leading Zeros From string in C++

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