threemax为什么是并非所有都有返回值？
namespace experience312
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
int k = 0;
class student
{
public string ne; double nr; public double em; public double mm; public double cm;
public double Nr { get { return nr; } set { if(value<0) nr=0;else nr=value;} }
public student(string nn, double n, double e, double m, double c) { this.ne = nn; this.nr = n; em = e; mm = m; cm = c; }
public double answer() { return em + mm + cm; }
}
class studentlist
{
private student[] Tom = new student[5];
public student this[int index]
{
get
{
if (index < 0 || index >= 5)
return Tom[0];
else return Tom[index];
}
set
{
if (index < 0 || index >= 5)
Tom[0] = value;
else
Tom[index] = value;
}
}
public string threeMax(int u, student[] number)
{
double t=0;
for (int z = 0; z <= u; z++)
{
for (int g = 1; g <= u; g++)
{
if (number[z].cm <= number[g].cm)
{
t = number[g].cm;
number[z].cm = number[u].cm;
number[u].cm = t;
return number[0].ne;
}
else { return number[0].ne; }
}
}
}
}
studentlist Internet = new studentlist();
private void button1_Click(object sender, EventArgs e)
{
string a = Convert.ToString(textBox1.Text);
double b = Convert.ToDouble(textBox3.Text);
double c = Convert.ToDouble(textBox3.Text);
double d = Convert.ToDouble(textBox4.Text);
double f = Convert.ToDouble(textBox5.Text);
Internet[k] = new student(a, b, c, d,f);
k++;
label9.Text = "已经添加了" + k + "个学生信息！";
}
private void button2_Click(object sender, EventArgs e)
{
string g=Convert.ToString(textBox6.Text);
for (int i = 0; i <= k-1; i++) {
if (Internet[i].ne ==g)
{label1.Text = Convert.ToString(Internet[i].answer());}
}
}
[解决办法]
你应该考虑到如果u=0，循环不起来，那么你是没有返回值的，改成如下试试
public string threeMax(int u, student[] number) { double t = 0; for (int z = 0; z <= u; z++) { for (int g = 1; g <= u; g++) { if (number[z].cm <= number[g].cm) { t = number[g].cm; number[z].cm = number[u].cm; number[u].cm = t; return number[0].ne; } else { return number[0].ne; } } } return string.Empty; }