Check for Integer Overflow Last Updated : 26 Mar, 2025 Comments Improve Suggest changes Like Article Like Report Given two integers a and b. The task is to design a function that adds two integers and detects overflow during the addition. If the sum does not cause an overflow, return their sum. Otherwise, return -1 to indicate an overflow.Note: You cannot use type casting to a larger data type to check for overflow. Also, the function must handle both positive and negative integers correctly.Examples:Input: a = 1000000000, b = 1000000000Output: 2000000000Explanation: The sum 1000000000 + 1000000000 = 2000000000 is within the valid integer range, so no overflow occurs, and the function stores the result successfully.Input: a = -2000000000, b = -500000000Output: -1Explanation: The sum -2000000000 + (-5000000000) = -7000000000 exceeds the maximum limit of an integer (assuming 32 bit representation), causing an overflow.Input: a = -100, b = 100Output: 0Explanation: The sum -100 + 100 = 0 is within the valid integer range, so no overflow occurs, and the function stores the result successfully.Table of Content[Expected Approach] Observation on Signs of the Integers - O(1) Time and O(1) Space[Alternate Approach] Checking the Sum - O(1) Time and O(1) Space[Expected Approach] Observation on Signs of the Integers - O(1) Time and O(1) SpaceThe idea is to detect overflow by observing how the sum behaves relative to the input values. The thought process is that overflow can only occur if both numbers have the same sign, but the sum has the opposite sign. The key observation is that in a typical integer representation, exceeding the maximum or minimum limit causes a wraparound effect, flipping the sign unexpectedly. By checking if this sign reversal happens, we can accurately determine overflow and return an error indicator.Calculate sumIf both numbers are positive and sum is negative then return -1OR If both numbers are negative and sum is positive then return -1Else return sum. C++ // C++ program to add two integers and detect overflow #include <bits/stdc++.h> using namespace std; // Function to add two numbers and check for overflow int addOvf(int a, int b) { // Calculate sum int sum = a + b; // Check for overflow conditions if ((a > 0 && b > 0 && sum < 0) || (a < 0 && b < 0 && sum > 0)) { return -1; } return sum; } int main() { int a = 1000000000, b = 1000000000; cout << addOvf(a, b) << endl; return 0; } Java // Java program to add two integers and detect overflow class GfG { // Function to add two numbers and check for overflow static int addOvf(int a, int b) { // Calculate sum int sum = a + b; // Check for overflow conditions if ((a > 0 && b > 0 && sum < 0) || (a < 0 && b < 0 && sum > 0)) { return -1; } return sum; } public static void main(String[] args) { int a = 1000000000, b = 1000000000; System.out.println(addOvf(a, b)); } } Python # Python program to add two integers and detect overflow # Function to add two numbers and check for overflow def addOvf(a, b): # Calculate sum sum = a + b # Check for overflow conditions if (a > 0 and b > 0 and sum < 0) or (a < 0 and b < 0 and sum > 0): return -1 return sum if __name__ == "__main__": a, b = 1000000000, 1000000000 print(addOvf(a, b)) C# // C# program to add two integers and detect overflow using System; class GfG { // Function to add two numbers and check for overflow static int addOvf(int a, int b) { // Calculate sum int sum = a + b; // Check for overflow conditions if ((a > 0 && b > 0 && sum < 0) || (a < 0 && b < 0 && sum > 0)) { return -1; } return sum; } public static void Main() { int a = 1000000000, b = 1000000000; Console.WriteLine(addOvf(a, b)); } } JavaScript // JavaScript program to add two integers and detect overflow // Function to add two numbers and check for overflow function addOvf(a, b) { // Calculate sum let sum = a + b; // Check for overflow conditions if ((a > 0 && b > 0 && sum < 0) || (a < 0 && b < 0 && sum > 0)) { return -1; } return sum; } let a = 1000000000, b = 1000000000; console.log(addOvf(a, b)); Output2000000000 Time Complexity: O(1), due to constant number of operations (addition and comparisons).Space Complexity: O(1), as only a few integer variables are used.[Alternate Approach] Checking the Sum - O(1) Time and O(1) SpaceThe idea remains the same as in the previous approach, checking for integer overflow while performing addition. Instead of relying on post-addition checks, we now prevent overflow before it happens by ensuring that the sum does not exceed Max Integer Value for positive numbers or go below Min Integer Value for negative numbers. C++ // C++ program to add two integers and detect overflow #include <bits/stdc++.h> using namespace std; // Function to add two numbers and check // for overflow int addOvf(int a, int b) { // Check for positive overflow if (a >= 0 && b >= 0 && (a > INT_MAX - b)) { return -1; } // Check for negative overflow else if (a < 0 && b < 0 && (a < INT_MIN - b)) { return -1; } // No overflow, compute sum int result = a + b; return result; } int main() { int a = 1000000000, b = 1000000000; cout << addOvf(a, b) << endl; return 0; } Java // Java program to add two integers and detect overflow class GfG { // Function to add two numbers and check // for overflow static int addOvf(int a, int b) { // Check for positive overflow if (a >= 0 && b >= 0 && (a > Integer.MAX_VALUE - b)) { return -1; } // Check for negative overflow else if (a < 0 && b < 0 && (a < Integer.MIN_VALUE - b)) { return -1; } // No overflow, compute sum int result = a + b; return result; } public static void main(String[] args) { int a = 1000000000, b = 1000000000; System.out.println(addOvf(a, b)); } } Python # Python program to add two integers and detect overflow # Function to add two numbers and check # for overflow def addOvf(a, b): # Check for positive overflow if a >= 0 and b >= 0 and (a > (2**31 - 1) - b): return -1 # Check for negative overflow elif a < 0 and b < 0 and (a < (-2**31) - b): return -1 # No overflow, compute sum result = a + b return result if __name__ == "__main__": a, b = 1000000000, 1000000000 print(addOvf(a, b)) C# // C# program to add two integers and detect overflow using System; class GfG { // Function to add two numbers and check // for overflow public static int addOvf(int a, int b) { // Check for positive overflow if (a >= 0 && b >= 0 && (a > int.MaxValue - b)) { return -1; } // Check for negative overflow else if (a < 0 && b < 0 && (a < int.MinValue - b)) { return -1; } // No overflow, compute sum int result = a + b; return result; } public static void Main() { int a = 1000000000, b = 1000000000; Console.WriteLine(addOvf(a, b)); } } JavaScript // JavaScript program to add two integers and detect overflow // Function to add two numbers and check // for overflow function addOvf(a, b) { // Check for positive overflow if (a >= 0 && b >= 0 && (a > Number.MAX_SAFE_INTEGER - b)) { return -1; } // Check for negative overflow else if (a < 0 && b < 0 && (a < Number.MIN_SAFE_INTEGER - b)) { return -1; } // No overflow, compute sum let result = a + b; return result; } // Driver Code let a = 1000000000, b = 1000000000; console.log(addOvf(a, b)); Output2000000000 Time Complexity: O(1), due to constant number of operations (addition and comparisons).Space Complexity: O(1), as only a few integer variables are used. Comment More infoAdvertise with us Next Article Find XOR of two number without using XOR operator kartik Follow Improve Article Tags : Bit Magic DSA integer-overflow Practice Tags : Bit Magic Similar Reads Bitwise Algorithms Bitwise algorithms in Data Structures and Algorithms (DSA) involve manipulating individual bits of binary representations of numbers to perform operations efficiently. These algorithms utilize bitwise operators like AND, OR, XOR, NOT, Left Shift, and Right Shift.BasicsIntroduction to Bitwise Algorit 4 min read Introduction to Bitwise Algorithms - Data Structures and Algorithms Tutorial Bit stands for binary digit. A bit is the basic unit of information and can only have one of two possible values that is 0 or 1. In our world, we usually with numbers using the decimal base. In other words. we use the digit 0 to 9 However, there are other number representations that can be quite use 15+ min read Bitwise Operators in C In C, bitwise operators are used to perform operations directly on the binary representations of numbers. These operators work by manipulating individual bits (0s and 1s) in a number.The following 6 operators are bitwise operators (also known as bit operators as they work at the bit-level). They are 6 min read Bitwise Operators in Java In Java, Operators are special symbols that perform specific operations on one or more than one operands. They build the foundation for any type of calculation or logic in programming.There are so many operators in Java, among all, bitwise operators are used to perform operations at the bit level. T 6 min read Python Bitwise Operators Python bitwise operators are used to perform bitwise calculations on integers. 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