练习7-7 矩阵运算 (20分)

题目来源：浙大版《C语言程序设计（第3版）》题目集 7-7

C语言代码

#include 
#include 

int* newMatrix(int n);//分配一块内存并存储矩阵元素
int sum(int* pp,int n);//计算题目要求的元素的和

void main()
{
	int s = 0;//存储结果
	int n;
	scanf("%d",&n);
	
	int* p = newMatrix(n);

	s = sum(p,n);
	printf("%d",s);
	free(p);
}

int* newMatrix(int n)
{
	int* pn = (int*)malloc(n*n*sizeof(int));
	int *pn1 = pn;
	int i = 0;
	while(i<n*n)
	{
		scanf("%d",pn1++);
		i++;
	}
	
	return pn;
}

int sum(int* pp,int n)
{
	int s = 0;
	int row = 0;
	for(int i = 1; i<=n*(n-1); i++)
	{
		
		if(i%n == 0) continue; //最后一列 
		if((i-1)%n == 0) row++;//当是每行第一个时，行数+1 
		if(i == row*n-(row-1)) continue; //副对角线 
		
		s += pp[i-1];
	}
	
	return s;
}