算法导论，合并排序，c实现。

/*INSERTION-SORT*/
//直接插入排序
#include<stdio.h>
int insertionsort(int A[],int n);
int mergesort(int A[],int p,int r);
int merge(int A[],int p,int q,int r);
int insertionSSort(int A[],int p,int r);
int main(void)
{
int A[10]={10,6,5,77,8,4,3000,9,12,1};
//mergesort(A,10);
insertionSSort(A,0,10);
//insertionsortsort(A,0,10);
int i;
for(i=0;i<10;i++)
printf("%d\n",A[i]);
return 0;

}
int insertionsort(int A[],int n)//升序
{
int j,i;

for(j=1;j<=n-1;j++)
{

int key=A[j];
i=j-1;
while(i>=0)
{
if(A[i]<key) break;//降序的话把使这里的A[i]>key
A[i+1]=A[i];
i=i-1;
}
A[i+1]=key;
}
}
int merge(int A[],int p,int q,int r)
{
int n1=q-p+1;
int n2=r-q;
int arrC[n1];
int arrD[n2];
int i;
for(i=0;i<n1;i++)
arrC[i]=A[p+i];
for(i=0;i<n2;i++)
arrD[i]=A[q+i+1];
//arrC[n1+1]=88888;
//arrD[n2+1]=88888;
i=0;
int j=0;
int k;
for(k=p;k<=r;k++)
{
if(i<n1&&j<n2){
if(arrC[i]<arrD[j])
{
A[k]=arrC[i];
i=i+1;
//continue;
}
else
{
A[k]=arrD[j];
j=j+1;
//continue;
}
}
else if(i>=n1&&j<n2)
{
A[k]=arrD[j];
j=j+1;
//continue;
}
else if(i<n1&&j>=n2)
{
A[k]=arrC[i];
i=i+1;
//continue;
}
}

}
int mergesort(int A[],int p,int r)//此代码数组0开头 并不是书上所写的1开头 合并排序
{
int q;
if(p<r)
{
q=(p+r)/2;
mergesort(A,p,q);
mergesort(A,q+1,r);
merge(A,p,q,r);
}
}
int insertionSSort(int A[],int p,int r)//习题2.3-4
{
if(p<r)
{

//--r;wrong
insertionSSort(A,p,r-1);
insertionsort(A,r);
}
}