Csharp/CSharp Tutorial/Language Basics/out
Содержание
Out Parameters
<source lang="csharp">using System; class Point {
public Point(int x, int y)
{
this.x = x;
this.y = y;
}
public void GetPoint(out int x, out int y)
{
x = this.x;
y = this.y;
}
int x;
int y;
} class MainClass {
public static void Main()
{
Point myPoint = new Point(10, 15);
int x;
int y;
myPoint.GetPoint(out x, out y);
Console.WriteLine("myPoint({0}, {1})", x, y);
}
}</source>
myPoint(10, 15)
Ref and Out Parameters
<source lang="csharp">using System; class Point {
public Point(int x, int y)
{
this.x = x;
this.y = y;
}
public void GetPoint(ref int x, ref int y)
{
x = this.x;
y = this.y;
}
int x;
int y;
} class MainClass {
public static void Main()
{
Point myPoint = new Point(10, 15);
int x = 0;
int y = 0;
myPoint.GetPoint(ref x, ref y);
Console.WriteLine("myPoint({0}, {1})", x, y);
}
}</source>
myPoint(10, 15)
Use out
<source lang="csharp">using System;
class Decompose {
public int parts(double n, out double frac) {
int whole;
whole = (int) n;
frac = n - whole; // pass fractional part back through frac
return whole; // return integer portion
}
}
class MainClass {
public static void Main() {
Decompose ob = new Decompose();
int i;
double f;
i = ob.parts(10.125, out f);
Console.WriteLine("Integer portion is " + i);
Console.WriteLine("Fractional part is " + f);
}
}</source>
Integer portion is 10 Fractional part is 0.125
Use "out" keyword (no need to assign because it is an out)
- An out parameter is used to pass a value out of a method.
- It is not necessary to give the variable used as an out parameter an initial value.
- An out parameter is always considered unassigned.
- The method must assign the parameter a value prior to the method"s termination.
<source lang="csharp">using System;
class MainClass
{
public static void Add(int x,int y, out int ans)
{
ans = x + y;
}
public static void Main()
{
Console.WriteLine("Adding 2 ints using out keyword");
int ans;
Add(90, 90, out ans);
Console.WriteLine("90 + 90 = {0}\n", ans);
}
}</source>
Adding 2 ints using out keyword 90 + 90 = 180
Use two out parameters
<source lang="csharp">using System;
class Num {
public bool hasComFactor(int x, int y,out int least, out int greatest) {
least = 1;
greatest = 1;
if(least != 1)
return true;
else
return false;
}
}
class MainClass {
public static void Main() {
Num ob = new Num();
int lcf, gcf;
if(ob.hasComFactor(231, 105, out lcf, out gcf)) {
Console.WriteLine("Lcf of 231 and 105 is " + lcf);
Console.WriteLine("Gcf of 231 and 105 is " + gcf);
}
else
Console.WriteLine("No common factor for 35 and 49.");
if(ob.hasComFactor(35, 51, out lcf, out gcf)) {
Console.WriteLine("Lcf of 35 and 51 " + lcf);
Console.WriteLine("Gcf of 35 and 51 is " + gcf);
}
else
Console.WriteLine("No common factor for 35 and 51.");
}
}</source>
No common factor for 35 and 49. No common factor for 35 and 51.
