c function to swap two numbers

1#include <stdio.h>
2int main() {
3    double a, b;
4    printf("Enter a: ");
5    scanf("%lf", &a);
6    printf("Enter b: ");
7    scanf("%lf", &b);
8
9    // Swapping
10
11    // a = (initial_a - initial_b)
12    a = a - b;   
13  
14    // b = (initial_a - initial_b) + initial_b = initial_a
15    b = a + b;
16
17    // a = initial_a - (initial_a - initial_b) = initial_b
18    a = b - a;
19
20    printf("After swapping, a = %.2lf\n", a);
21    printf("After swapping, b = %.2lf", b);
22    return 0;
23}
24

1#include <stdio.h>
2 
3void swap(int*, int*);
4 
5int main()
6{
7   int x, y;
8 
9   printf("Enter the value of x and y\n");
10   scanf("%d%d",&x,&y);
11 
12   printf("Before Swapping\nx = %d\ny = %d\n", x, y);
13 
14   swap(&x, &y); 
15 
16   printf("After Swapping\nx = %d\ny = %d\n", x, y);
17 
18   return 0;
19}
20 
21void swap(int *a, int *b)
22{
23   int temp;
24 
25   temp = *b;
26   *b = *a;
27   *a = temp;   
28}
29 

1#include <stdio.h>
2int main()
3{
4    int a, b, temp;
5    printf("enter the values of a and b: \n");
6    scanf("%d%d", &a, &b );
7    printf("current values are:\n a=%d\n b=%d\n", a, b);
8    temp=a;
9    a=b;
10    b=temp;
11    printf("After swapping:\n a=%d\n b=%d\n", a, b);
12}

1#include<stdio.h>
2
3void swap(int *,int *);
4int main()
5{
6
7    int n1,n2;
8	printf("\n\n Function : swap two numbers using function :\n");
9	printf("------------------------------------------------\n");	   
10    printf("Input 1st number : ");
11    scanf("%d",&n1);
12    printf("Input 2nd number : ");
13    scanf("%d",&n2);	
14
15    printf("Before swapping: n1 = %d, n2 = %d ",n1,n2);
16	//pass the address of both variables to the function.
17    swap(&n1,&n2);
18
19    printf("\nAfter swapping: n1 = %d, n2 = %d \n\n",n1,n2);
20    return 0;
21}
22
23void swap(int *p,int *q)
24{
25	//p=&n1 so p store the address of n1, so *p store the value of n1
26	//q=&n2 so q store the address of n2, so *q store the value of n2
27
28    int tmp;
29    tmp = *p; // tmp store the value of n1
30    *p=*q;    // *p store the value of *q that is value of n2
31    *q=tmp;   // *q store the value of tmp that is the value of n1
32}
33
34

1#include <stdio.h>
2#include <stdlib.h>
3
4int main()
5{
6  	//initialize variables
7	int num1 = 10;
8	int num2 = 9;
9  	int tmp;
10  	
11  	//create the variables needed to store the address of the variables
12  	//that we want to swap values
13  	int *p_num1 = &num1;
14  	int *p_num2 = &num2;
15  
16  	//print what the values are before the swap
17  	printf("num1: %i\n", num1);
18    printf("num2: %i\n", num2);
19  
20  	//store one of the variables in tmp so we can access it later
21  	//gives the value we stored in another variable the new value
22  	//give the other variable the value of tmp
23  	tmp = num1;
24  	*p_num1 = num2;
25  	*p_num2 = tmp;
26
27  	//print the values after swap has occured
28   	printf("num1: %i\n", num1);
29    printf("num2: %i\n", num2);
30  	
31	return 0;
32}
33