# C - Swap two numbers

There are two common ways to swap the value of two variables:

• Swap the value of two variables using a temporary variable
• Swap the value of two variables without using temporary variable

### Method 1: Swap the value of two variables using a temporary variable

In the example below, the initial value of variables x and y are 10 and 25. A temporary variable called temp is created to store the value of x and then the value of y is assigned to x. Finally, value of temp (which stores values of x) is assigned to variable y. The final value of variables x and y after swap are 25 and 10 respectively.

```#include <stdio.h>

static void swap(int, int);

static void swap(int x, int y) {
printf("Before Swap.\n");
printf("x = %i\n", x);
printf("y = %i\n", y);

//Swap technique
int temp = x;
x = y;
y = temp;

printf("After Swap.\n");
printf("x = %i\n", x);
printf("y = %i\n", y);
}

int main() {
swap(10, 25);
}
```

The above code will give the following output:

```Before Swap.
x = 10
y = 25
After Swap.
x = 25
y = 10
```

### Method 2: Swap the value of two variables without using temporary variable

+ operator is used to swap the value of two variables. In this method no temporary variable is used. Please see the example below for syntax.

```#include <stdio.h>

static void swap(int, int);

static void swap(int x, int y) {
printf("Before Swap.\n");
printf("x = %i\n", x);
printf("y = %i\n", y);

//Swap technique
x = x + y;
y = x - y;
x = x - y;

printf("After Swap.\n");
printf("x = %i\n", x);
printf("y = %i\n", y);
}

int main() {
swap(10, 25);
}
```

The above code will give the following output:

```Before Swap.
x = 10
y = 25
After Swap.
x = 25
y = 10
```

Similarly, others operators can also be used in this method. Please see the page: C - Swap two numbers without using Temporary Variable.

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