#include <iostream>
using namespace std;

typedef int ElemType;

void SymmetricMatrixStore(int n, ElemType*& s);//存储n行的对称矩阵,将存储结果放入数组s中返回
void TraverseSymmetricMatrix(ElemType* s, int n);//将存储在数组s中的n行对称矩阵遍历

void UpperTriangularMatrixStore(int n, ElemType*& s);//存储n行的上三角矩阵,将存储结果放入数组s中返回
void TraverseUpperTriangularMatrix(ElemType* s, int n);//将存储在数组s中的n行上三角矩阵遍历

void LowerTriangularMatrixStore(int n, ElemType*& s);//存储n行的下三角矩阵,将存储结果放入数组s中返回
void TraverseLowerTriangular(ElemType* s, int n);//将存储在数组s中的n行下三角矩阵遍历

void TridiagonalMatrixStore(int n, ElemType*& s);//存储n行的三对角矩阵,将存储结果放入数组s中返回
void TraverseTridiagonalMatrix(ElemType* s, int n);//将存储在数组s中的n行三对角矩阵遍历


void SymmetricMatrixStore(int n, ElemType*& s) {
	s = new ElemType[n * (n + 1) / 2];
	if (!s)exit(0);
	int length = n * (n + 1) / 2;
	cout << "请按行顺序输入对称矩阵的值：" << endl;
	for (int i = 0; i < length; i++)
		cin >> s[i];
}
void TraverseSymmetricMatrix(ElemType* s, int n) {
	int k = 0;
	cout << "---------对称矩阵---------" << endl;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i >= j)k = i * (i + 1) / 2 + j;
			else k = j * (j + 1) / 2 + i;
			cout << s[k] << "  ";
		}
		cout << endl;
	}
	cout << "--------------------------" << endl;
}
void UpperTriangularMatrixStore(int n, ElemType*& s) {
	s = new ElemType[n * (n + 1) / 2 + 1];
	if (!s)exit(0);
	int length = n * (n + 1) / 2;
	cout << "请按行顺序输入上三角矩阵的三角部分值：" << endl;
	for (int i = 0; i < length; i++)
		cin >> s[i];
	cout << "请输入一位下三角区元素："; 
	cin >> s[length];
}
void TraverseUpperTriangularMatrix(ElemType* s, int n) {
	int k = 0;
	cout << "---------上三角矩阵---------" << endl;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i > j)k = n * (n + 1) / 2;
			else k = i * (2 * n - i + 1) / 2 + (j - i);
			cout << s[k] << "  ";
		}
		cout << endl;
	}
	cout << "----------------------------" << endl;
}
void LowerTriangularMatrixStore(int n, ElemType*& s) {
	s = new ElemType[n * (n + 1) / 2 + 1];
	if (!s)exit(0);
	int length = n * (n + 1) / 2;
	cout << "请按行顺序输入下三角矩阵的三角部分值：" << endl;
	for (int i = 0; i < length; i++)
		cin >> s[i];
	cout << "请输入一位上三角区元素：";
	cin >> s[length];
}
void TraverseLowerTriangular(ElemType* s, int n) {
	int k = 0;
	cout << "---------下三角矩阵---------" << endl;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i < j)k = n * (n + 1) / 2;
			else k = i * (i + 1) / 2 + j;
			cout << s[k] << "  ";
		}
		cout << endl;
	}
	cout << "----------------------------" << endl;
}
void TridiagonalMatrixStore(int n, ElemType*& s) {
	s = new ElemType[3 * n - 2];
	if (!s)exit(0);
	int length = 3 * n - 2;
	cout << "请按行顺序输入三对角矩阵的值：" << endl;
	for (int i = 0; i < length; i++)
		cin >> s[i];
}
void TraverseTridiagonalMatrix(ElemType* s, int n) {
	int k = 0;
	cout << "---------下三角矩阵---------" << endl;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (j - i >= -1 && j - i <= 1) {
				cout << s[k] << "  ";
				k++;
			}
			else
				cout << 0 << "  ";
		}
		cout << endl;
	}
	cout << "----------------------------" << endl;
}


int main()
{
	int n = 0;
	cout << "请输入矩阵维数：";
	cin >> n;
	int* s;
	SymmetricMatrixStore(n, s);
	TraverseSymmetricMatrix(s, n);
	delete[] s;

	UpperTriangularMatrixStore(n, s);
	TraverseUpperTriangularMatrix(s, n);
	delete[] s;

	LowerTriangularMatrixStore(n, s);
	TraverseLowerTriangular(s, n);
	delete[] s;

	TridiagonalMatrixStore(n, s);
	TraverseTridiagonalMatrix(s, n);
	delete[] s;
	return 0;
}

实验样例