merge.cm

来自「一个c语言的编译器的源代码」· CM 代码 · 共 97 行

void in(int a[], int n)
{
    int i;
    i = 0;
    while (i < n)
    {
        a[i] = input();
        i = i + 1;
    }
    return;
}

void out(int a[], int n)
{
    int i;
    i = 0;
    while (i < n)
    {
        output(a[i]);
        i = i + 1;
    }
    return;
}

void mergesort(int a[], int n)
{
    if (n > 1)
    {
        int b[50];
        int c[50];
        int i;
        int j;
        int k;
        int r;
        int s;
        int t;
        r = n / 2;
        s = n - n / 2;
        i = 0; 
        while (i < r)
        {
            b[i] = a[i];
            i = i + 1;
        }
        while (i < n)
        {
            c[i - r] = a[i];
            i = i + 1;
        }
        mergesort(b, r);
        mergesort(c, s);
        i = j = k = 0;
        t = 1;
        while (t==1)
        {
            if (b[i] < c[j])
            {
                a[k] = b[i];
                i = i + 1;
            }
            else
            {
                a[k] = c[j];
                j = j + 1;
            }
            k = k + 1;
            if (i >= r)
                t = 0;
            if (j >= s)
                t = 0;
        }
        while (i < r)
        {
            a[k] = b[i];
            i = i + 1;
            k = k + 1;
        }
        while (j < s)
        {
            a[k] = c[j];
            j = j + 1;
            k = k + 1;
        }
    }
    return;
}

void main(void)
{
    int a[100];
    int n;
    n = input();
    in(a, n);
    mergesort(a, n);
    out(a, n);
    return;
}