BubbleSort@pointers,functions

#include<stdio.h>

void swap(int* a, int* b);

int main(){

    int first=0,last=0,n=0,i=0,j=0,arr[15];

    printf("enter the size of the array(less than 15): ");
    scanf("%d",&n);
    printf("enter the array members: ");
    for(i=0;i<n;i++){
        scanf("%d",&arr[i]);
    }
    printf("\nthe entered array: ");
        for(i=0;i<n;i++){
            printf("%d ",arr[i]);
    }

    last=(n-1);

    //bubble sort
    for(i=last;i>first;i--){

        for(j=first;j<last;j++){

            if(arr[j]>arr[j+1]){
                swap(&arr[j],&arr[j+1]);
            }
        }
    }
    printf("\nthe sorted array: ");
        for(i=0;i<n;i++){
            printf("%d ",arr[i]);
    }
    return 0;
}

void swap(int* a, int* b){
    *a=*a + *b;
    *b=*a-*b;
    *a=*a-*b;
}