C#做的用海伦公式计算三角形面积

软件截图设计：

软件代码：

using System;

using System.Collections.Generic;

using https://www.360docs.net/doc/32609428.html,ponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace三角形面积计算

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

button1.Enabled = false;

}

private void Form1_Load(object sender, EventArgs e)

{

label1.Text = " 假设在平面内，有一个三角形，边长分别为a、b、c，三角形的面积S可由以下公式求得：\r\n \r\n S=√[p(p-a)(p-b)(p-c)] ";

button2.Enabled = false;

tba.Focus();

}

private void textBox1_TextChanged(object sender, EventArgs e)

{

if (tba.Text.Length != 0 || tbb.Text.Length != 0 || tbc.Text.Length != 0 ||

tbr.Text.Length != 0)

{

button2.Enabled = true;

}

else if (tba.Text.Length == 0 || tbb.Text.Length == 0 || tbc.Text.Length == 0 || tbr.Text.Length == 0)

{

button2.Enabled = false;

}

}

private void button1_Click(object sender, EventArgs e)

{

//tba,tbb,tbc分别为a,b,c后面的textBox1，textBox2，textBox3

double S, a,b,c,p;

a=Convert.ToDouble(tba.Text);

b=Convert.ToDouble(tbb.Text);

c=Convert.ToDouble(tbc.Text);

if ((a + b > c) && (a + c > b) && (b + c > a))

{

p = (a + b + c) / 2;

S = Math.Sqrt(p * (p - a) * (p - b) * (p - c));

tbr.Text = S.ToString();

}

else

{

MessageBox.Show("所输数据无法构成三角形，\r\n请检查数据后输入！");

tba.Focus();

tba.Text = "";

tbb.Text = "";

tbc.Text = "";

tbr.Text = "";

button1.Enabled = false;

button2.Enabled = false;

}

}

private void button2_Click(object sender, EventArgs e)

{

tba.Focus();

tba.Text = "";

tbb.Text = "";

tbc.Text = "";

tbr.Text = "";

button1.Enabled = false;

button2.Enabled = false;

}

private void button3_Click(object sender, EventArgs e)

{

Application.Exit();

}

private void zhiyanzheng_KeyPress(object sender, KeyPressEventArgs e)

{

if ((e.KeyChar < 48 || e.KeyChar > 57) && e.KeyChar != 8 && e.KeyChar!=46) {

e.Handled = true;

}

}

private void txtboxEmpty_Validating(object sender, CancelEventArgs e)

{

if (tba.Text.Length != 0 && tbb.Text.Length != 0 && tbc.Text.Length != 0) {

button1.Enabled = true;

}

}

}

}