📘 Lesson · Lesson 61

Swap Without Third Variable

The Trick

💡 Note

You can swap two numbers without a temporary variable using arithmetic or XOR.

Using Arithmetic

#include <stdio.h>
int main() {
    int a = 5, b = 9;
    a = a + b;   // 14
    b = a - b;   // 5
    a = a - b;   // 9
    printf("a=%d b=%d", a, b);
    return 0;
}

Output:
a=9 b=5

Summary

Add then subtract to swap without a third variable.
XOR (^) also works: a^=b; b^=a; a^=b;

तरकीब

💡 Note

आप बिना temporary variable के दो numbers swap कर सकते हैं arithmetic या XOR से।

Arithmetic से

#include <stdio.h>
int main() {
    int a = 5, b = 9;
    a = a + b;   // 14
    b = a - b;   // 5
    a = a - b;   // 9
    printf("a=%d b=%d", a, b);
    return 0;
}

Output:
a=9 b=5

सारांश

Add फिर subtract करके बिना third variable swap करें।
XOR (^) भी काम करता है: a^=b; b^=a; a^=b;

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