MergeSort - Divide and Conquer

[xgiovio]

#include <iostream>

using namespace std;

void x_merge (int * first_array, int size1, int * second_array, int size2){

    int i,j,k;
    int * third_array = new int [size1 + size2];

    for(i=0, j=0, k=-1 ; (i<size1) && (j<size2) ;){
        if ( *(first_array + i) <= *(second_array + j)  ){
            ++k;
            *(third_array + k) =  *(first_array + i);
            ++i;
        } else {
            ++k;
            *(third_array + k) =  *(second_array + j);
            ++j;
        }
    }
    if( i>= size1 ){
        for(;j<size2;){
            ++k;
            *(third_array + k) =  *(second_array + j);
            ++j;
        }
    } else {
        for(;i<size1;){
            ++k;
            *(third_array + k) =  *(first_array + i);
            ++i;
        }
    }


    for(i=0; i<size1 ;++i){
        *(first_array + i) = *(third_array + i);
    }
    j=i;
    for(i=0; i<size2 ;++i){
        *(second_array + i) = *(third_array + i + j);
    }
    delete [] third_array ;
}



void x_mergesort(int * array, int size){

    if (size == 2){
        int a,b,c;
        a=*array;
        b=*(array + 1 );
        if (b < a ){
            c= *array;
            *array = b;
            *(array +1) = c;
        }
    }else{
        if (size > 2){
            x_mergesort( array, (size/2));
            x_mergesort(array + (size/2),size - (size/2));
            x_merge(array, (size/2), array + (size/2), size - (size/2));
        }
    }
}


void x_print (int * array, int size){
    int i;
    for(i=0;i<size;++i){
        cout <<  * (array + i) << endl;
    }
}




int main () {
    
    int numeri [] = {1,10,5,3,345,2,33,22,44,33,1,2,4,2,5,8,3,9,4,445,22,334,54};
        x_mergesort(numeri,23);
        x_print(numeri,23);

        cin.get();
return 0;

}