Data Modelling & AI Data Structure & Algorithm

Remove trailing zeros from the sum of two numbers ( Using Stack )

23 June 2025

2

Given two numbers A and B, the task is to remove the trailing zeros present in the sum of the two given numbers using a stack.

Examples:

Input: A = 124, B = 186
Output: 31
Explanation: Sum of A and B is 310. Removing the trailing zeros modifies the sum to 31.

Input: A=130246, B= 450164
Output : 58041

Approach: The given problem can be solved using the string and stack data structures. Follow the steps below to solve the problem:

Calculate A + B and store it in a variable, say N.
Initialize a stack < char >, say S, to store the digits of N.
Convert the integer N to string and then push the characters into the stack S.
Iterate while S is not empty(), If the top element of the stack is ‘0’, then pop it out of the stack. Otherwise, break.
Initialize a string, say res, to store the resultant string.
Iterate while S is not empty(), and push all the characters in res and, then pop the top element.
Reverse the string res and print the res as the answer.

Below is the implementation of the above approach:

C++14

// C++ program for the above approach
#include <bits/stdc++.h>
using namespace std;
 
// Function to remove trailing
// zeros from the sum of two numbers
string removeTrailing(int A, int B)
{
    // Stores the sum of A and B
    int N = A + B;
 
    // Stores the digits
    stack<int> s;
 
    // Stores the equivalent
    // string of integer N
    string strsum = to_string(N);
 
    // Traverse the string
    for (int i = 0; i < strsum.length(); i++) {
 
        // Push the digit at i
        // in the stack
        s.push(strsum[i]);
    }
 
    // While top element is '0'
    while (s.top() == '0')
 
        // Pop the top element
        s.pop();
 
    // Stores the resultant number
    // without trailing 0's
    string res = "";
 
    // While s is not empty
    while (!s.empty()) {
 
        // Append top element of S in res
        res = res + char(s.top());
 
        // Pop the top element of S
        s.pop();
    }
 
    // Reverse the string res
    reverse(res.begin(), res.end());
 
    return res;
}
 
// Driver Code
int main()
{
    // Input
    int A = 130246, B = 450164;
 
    // Function Call
    cout << removeTrailing(A, B);
    return 0;
}

Java

// Java program for the above approach
import java.io.*;
import java.util.*;
 
class GFG{
 
// Function to remove trailing
// zeros from the sum of two numbers
static String removeTrailing(int A, int B)
{
     
    // Stores the sum of A and B
    int N = A + B;
 
    // Stores the digits
    Stack<Character> s = new Stack<Character>();
 
    // Stores the equivalent
    // string of integer N
    String strsum = Integer.toString(N);
 
    // Traverse the string
    for(int i = 0; i < strsum.length(); i++) 
    {
         
        // Push the digit at i
        // in the stack
        s.push(strsum.charAt(i));
    }
 
    // While top element is '0'
    while (s.peek() == '0')
    {
         
        // Pop the top element
        s.pop();
    }
 
    // Stores the resultant number
    // without trailing 0's
    String res = "";
 
    // While s is not empty
    while (s.empty() == false) 
    {
         
        // Append top element of S in res
        res = res + (char)s.peek();
 
        // Pop the top element of S
        s.pop();
    }
 
    StringBuilder str = new StringBuilder();
    str.append(res);
 
    // Reverse the string res
    str.reverse();
 
    return str.toString();
}
 
// Driver Code
public static void main (String[] args) 
{
     
    // Input
    int A = 130246, B = 450164;
 
    // Function Call
    System.out.println(removeTrailing(A, B));
}
}
 
// This code is contributed by Dharanendra.L.V.

Python3

# Python 3 program for the above approach
 
# Function to remove trailing
# zeros from the sum of two numbers
def removeTrailing(A,  B):
 
    # Stores the sum of A and B
    N = A + B
 
    # Stores the digits
    s = []
 
    # Stores the equivalent
    # string of integer N
    strsum = str(N)
 
    # Traverse the string
    for i in range(len(strsum)):
 
        # Push the digit at i
        # in the stack
        s.append(strsum[i])
 
    # While top element is '0'
    while (s[-1] == '0'):
 
        # Pop the top element
        s.pop()
 
    # Stores the resultant number
    # without trailing 0's
    res = ""
 
    # While s is not empty
    while (len(s) != 0):
 
        # Append top element of S in res
        res = res + (s[-1])
 
        # Pop the top element of S
        s.pop()
 
    # Reverse the string res
    res = list(res)
    res.reverse()
    res = ''.join(res)
 
    return res
 
 
# Driver Code
if __name__ == "__main__":
 
    # Input
    A = 130246
    B = 450164
 
    # Function Call
    print(removeTrailing(A, B))
 
    # This code is contributed by ukasp.

C#

// C# program for the above approach
using System;
using System.Collections.Generic;
 
class GFG{
     
// Function to remove trailing
// zeros from the sum of two numbers
static string removeTrailing(int A, int B)
{
     
    // Stores the sum of A and B
    int N = A + B;
  
    // Stores the digits
    Stack<char> s = new Stack<char>();
  
    // Stores the equivalent
    // string of integer N
    string strsum = N.ToString();
  
    // Traverse the string
    for(int i = 0; i < strsum.Length; i++)
    {
          
        // Push the digit at i
        // in the stack
        s.Push(strsum[i]);
    }
  
    // While top element is '0'
    while (s.Peek() == '0')
    {
          
        // Pop the top element
        s.Pop();
    }
  
    // Stores the resultant number
    // without trailing 0's
    string res = "";
  
    // While s is not empty
    while (s.Count != 0)
    {
          
        // Append top element of S in res
        res = res + (char)s.Peek();
  
        // Pop the top element of S
        s.Pop();
    }
     
    char[] str = res.ToCharArray();
    Array.Reverse(str);
     
    // Reverse the string res
    return new string( str);
}
  
// Driver Code
static public void Main()
{
     
    // Input
    int A = 130246, B = 450164;
     
    // Function Call
    Console.WriteLine(removeTrailing(A, B));
}
}
 
// This code is contributed by avanitrachhadiya2155

Javascript

<script>
 
        // Javascript program for the above approach
 
        // Function to remove trailing
        // zeros from the sum of two numbers
        function removeTrailing(A, B) {
 
            // Stores the sum of A and B
            let N = A + B;
 
            // Stores the digits
            let s = new Array();
 
            // Stores the equivalent
            // string of integer N
            let strsum = N.toString();
 
            // Traverse the string
            for (let i = 0; i < strsum.length; i++) {
 
                // Push the digit at i
                // in the stack
                s.push(strsum.charAt(i));
            }
 
            // While top element is '0'
            while (s[s.length-1] === '0') {
 
                // Pop the top element
                s.pop();
            }
        
            // Stores the resultant number
            // without trailing 0's
            let res = "";
 
            // While s is not empty
            while (s.length != 0) {
 
                // Append top element of S in res
                res = res.concat(s[s.length-1]);
 
                // Pop the top element of S
                s.pop();
            }
 
            let str = "";
            str = str.concat(res)
 
            // Reverse the string res
            str = str.split("").reverse().join("");
 
            return str.toString();
        }
 
        // Driver Code
 
        // Input
        let A = 130246, B = 450164;
 
        // Function Call
        document.write(removeTrailing(A, B));
 
        // This code is contributed by Hritik
         
    </script>

Output:

Time Complexity: O(len(A + B))
Auxiliary Space: O(len(A + B))

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Remove trailing zeros from the sum of two numbers ( Using Stack )

C++14

Java

Python3

C#

Javascript

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