C PROGRAMMING PROGRAM • OPERATORS & CONVERSIONS

Swap Two Numbers Without a Temporary Variable

Learn how to swap two numbers without a temporary variable using a clear C program.

BeginnerArithmetic assignmentSwapVariables

PROBLEM UNDERSTANDING

Input and expected output

Sample input

10 25

Sample output

After swapping: 25 10

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    long long first, second;

    printf("Enter two integers: ");
    scanf("%lld %lld", &first, &second);
    first = first + second;
    second = first - second;
    first = first - second;
    printf("After swapping: %lld %lld\n", first, second);
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

After swapping: 25 10

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Store the combined value temporarily in one variable and recover both values by subtraction.
Display the computed result.

Store the combined value temporarily in one variable and recover both values by subtraction.

EFFICIENCY

Time and space complexity

Time complexity

O(1)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

Arithmetic swapping may overflow for very large integers.

Check this

Do not change the order of the three assignments.

Check this

Prefer a temporary variable in production code for clarity.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.