if((a %4==0 && a %100!=0) || a %400 == 0)
{
MessageBox.Show ("是闰年");
}
else
{
MessageBox.Show("不是闰年");
}
}
或办法
int a = int.Parse(textBox1 .Text );
string s = (a % 4 == 0 ? "该年份是闰年": "该年份是平年" );
}
else if(textBox2.Text ==("-"))
{
MessageBox.Show((num1-num2).ToString());
17）用while和do-while求1-100之间所有整数的和，积等17
18）类的创建和使用（类的声明，字段，属性和方法的添加，生成类的实例和使用其成员）17
19）format的用法18
1
private void button1_Click(object sender, EventArgs e)
{
intbai = i / 100;
if(i == bai * bai * bai + shi * shi * shi + ge * ge * ge)
{
s += i.ToString() +"\r\n";
}
}
MessageBox.Show(s,"你好漂亮");
}
}
6
private void button1_Click(object sender, EventArgs e)
{
float num1 = Convert.ToInt32(textBox1.Text);
float num2 = Convert.ToInt32(textBox3.Text);
if (textBox2.Text ==("+"))
{
MessageBox.Show((num1+num2).ToString());
{
a = i % 7;
if (a == 0)
{
sum = sum + i;
}
}
textBox1.Text = sum.ToString();
}
4
private void button1_Click(object sender, EventArgs e)
{
int a = Convert.ToInt32(textBox1.Text);
{
double a = double.Parse(txb_A.Text),
b = double.Parse(txb_B.Text),
c = double.Parse(txb_C.Text);
if (a == 0)
{
MessageBox.Show("方程的根是：" + (-c / b).ToString());
MessageBox.Show(s)
5
privatevoidbutton1_Click(objectsender,EventArgse)
{
strings ="水仙花数:"+"\r\n";
for(inti = 100; i < 1000; i++)
{
intge = i % 10;
intshi = i / 10 % 10;
{
sum = sum + i;
}
textBox1.Text = sum.ToString();
private void button1_Click(object sender, EventArgs e)
{
int sum = 0;
int a;
for (int i = 0; i <= 100; i++)
9）圆台的体积8
10）三角形的三边，求三角形的面积8
11）乘法口诀表9
12）字符串的统计（大写，小写字母，数字的个数）9
13）数值类型的转换：数值-字符串，字符串-数字，数值类型之间的显示转换，隐式转换10
14）遍历窗体上的组件14
15）随机数发生器的用法15
16）用switch判断成绩等级，改变窗体的背景颜色15
int s = int.Parse(textBox1.Text.Trim());
if (s >= 90 && s <= 100)
{
MessageBox.Show("优秀");
}
else if (s >= 80 && s < 90)
{
MessageBox.Show("良好");
}
else if (s >= 70 && s < 80)
}
else
{
double delta = Math.Pow(b, 2) - 4 * a * c;
if (delta >= 0)
{
double X1 = (-b + Math.Pow(delta, 0.5)) / 2 * a;
double X2 = (-b - Math.Pow(delta, 0.5)) / 2 * a;
{
int sum = 0;
for (int i = 0; i <= 100; i = i +1)
{
sum = sum + i;
}
textBox1.Text = sum.ToString();
}
求1~100之内所有偶数的和
int sum = 0;
for (int i = 0; i <= 100; i = i + 2)
1）2
2）一元二次方程求解2
3）1-100之间所有整数的和，能被某数整除的所有整数的和，积3
4）闰年的判断4
5）水仙花数4
6）简单计算器5
7）一维数组的声明、初始化、赋值、遍历（求数组所有元素的和，积，最大值，最小值等统计数值）6
8）二维数组的声明、初始化、赋值、遍历（求数组所有元素的和，积，最大值，最小值等统计数值）7
string temp = "X1="+X1.ToString()+"\r\nX2="+X2.ToString();
MessageBox.Show(temp);
}
else
{
MessageBox.Show("没有实数根！");
}
}
}
3
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("中");
}
else if (s >= 60 && s < 70)
{
MessageBox.Show("及格");
}
else
{
MessageBox.Show("不及格");
}
}
2
private void button1_Click(object sender, EventArgs e)