归并排序

void mergesort(int *,int *,unsigned int,unsigned int);
void msort(int *arr,int cont);
int main(int argc,const char *argv[])
{
    int arr_1[16] = {0}, arr_2[16] = {0};
    int i = 0;
    printf("arr_1:");
    for(;i<16;i++){
        arr_1[i] = rand()%100;
        printf("%d ",arr_1[i]);
    }
    printf("\n");

/*
    printf("arr_2:");
    for(;i<16;i++){
        arr_2[i] = rand()%100;
        printf("%d ",arr_2[i]);
    }
    printf("\n");
*/

    msort(arr_1,16);
    printf("\narr_1:");
    for(i=0;i<16;i++){
        printf("%d ",arr_1[i]);
    }
    printf("\n");
    
    return 0;
}
void mergesort(int *arr,int *arrtmp,unsigned int start,unsigned int end){
    if( start>=end )return;

    int mid = start+(end-start)/2;
    int istart1=start,iend1=mid;
    int istart2=mid+1,iend2=end;

    mergesort(arr,arrtmp,istart1,iend1);
    mergesort(arr,arrtmp,istart2,iend2);

    int ii = start;

    while(istart1<=iend1 && istart2<=iend2)
        arrtmp[ii++]=arr[istart1]<arr[istart2]?arr[istart1++]:arr[istart2++];
    while(istart1<=iend1)
        arrtmp[ii++]=arr[istart1++];
    while(istart2<=iend2)
        arrtmp[ii++]=arr[istart2++];
    memcpy(arr+start,arrtmp+start,(end-start+1)*sizeof(int));
}

void msort(int *arr,int cont){
    if(cont <2 )return;
    int arrtmp[cont];
    mergesort(arr,arrtmp,0,cont-1);
}