ืืื ืฉืืืช Java System.arraycopy()?
ืืฆืืจืช ืฉืืืช Java System.arraycopy()โ
ืืฆืืจืช ืืฉืืื ืขืืืจ ืฉืืืช java.lang.System.arraycopy() ืืืืืงื java.lang ืืื ืืืืงืื:public static void arraycopy(Object src, int srcIndex, Object dest, int destIndex, int len)
ืคืจืืืจืื
ืืืื ืืคืจืืืจืื ืฉื ืฉืืืช arraycopy :-
src : ืืื ืืขืจื ืืืงืืจ.
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srcIndex : ืืื ืืื ืืงืก ืืืชืืื ืฉื ืืขืจื ืืืงืืจ.
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dest : ืืื ืืขืจื ืืืขื.
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destIndex : ืืื ืืื ืืงืก ืืืชืืื ืฉื ืืขืจื ืืืขื.
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len : ืืื ืืกืคืจ ืืืืื ืืื ืฉืฆืจืื ืืืขืชืืง ืืืขืจื ืืืงืืจ ืืืขืจื ืืืขื.
ืคืื ืงืฆืืื ืืืืช
ืฉืืืช arraycopy ืืขืชืืงื ื ืชืื ืื ื- src , ืืื ืืจืืืื srcIndex ืขื srcIndex +( len - 1), ืืืขืจื ื-dest ื- destIndex ืขื destIndex + ( len - 1).ืขืจื ืืืืจื
ืืฉืืืช arraycopy ืืฉ ืกืื ืืืืจื ืจืืง ืื ืฉืืืืจ ืฉืืื ืื ืืืืืจื ืืืื.ืืืืื
public class Example {
public static void main(String[] args) {
String[] src = { "Monday","Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
String[] dest = { "January", "February", "March", "April", "May", "June", "July", "August"};
int srcIndex = 2;
int destIndex = 3;
int len = 2;
//print number of elements that need to be copied
//from the source to the destination array
System.out.println("len : " + len);
//print source index
System.out.println("srcIndex : " + srcIndex);
//print elements of the source array
System.out.print("src : ");
for (int i = 0; i < src.length; i++)
System.out.print(src[i] + " ");
System.out.println("");
//print destination index
System.out.println("destIndex : " + destIndex);
//print elements of the destination array
System.out.print("dest : ");
for (int i = 0; i < dest.length; i++)
System.out.print(dest[i] + " ");
System.out.println("");
// Use of arraycopy() method
System.arraycopy(src, srcIndex, dest, destIndex, len);
// this method copies the 'len' no of elements
// from the src array to the dest array using the srcIndex
// and destIndex as reference points in both the arrays
// Print elements of destination after
System.out.print("final destination array : ");
for (int i = 0; i < dest.length; i++)
System.out.print(dest[i] + " ");
}
}
ืชึฐืคืึผืงึธื
len: 2 srcIndex: 2 src: ืฉื ื ืฉืืืฉื ืจืืืขื ืืืืฉื ืฉืืฉื ืฉืืช ืจืืฉืื destIndex: 3 ืืขื: ืื ืืืจ ืคืืจืืืจ ืืจืฅ ืืคืจืื ืืื ืืื ื ืืืื ืืืืืกื ืืขืจื ืืขื ืกืืคื: ืื ืืืจ ืคืืจืืืจ ืืจืฅ ืจืืืขื ืืืืฉื ืืื ื ืืืื ืืืืืกื
ืืืืื ืืฉืื ืื ืคืจืืืจืื
// Example of changing parameters
srcIndex = 4;
destIndex = 5;
len = 1;
ืชึฐืคืึผืงึธื
len: 1 srcIndex: 4 src: ืฉื ื ืฉืืืฉื ืจืืืขื ืืืืฉื ืฉืืฉื ืฉืืช ืจืืฉืื destIndex: 5 ืืขื: ืื ืืืจ ืคืืจืืืจ ืืจืฅ ืืคืจืื ืืื ืืื ื ืืืื ืืืืืกื ืืขืจื ืืขื ืกืืคื: ืื ืืืจ ืคืืจืืืจ ืืจืฅ ืืคืจืื ืืื ืฉืืฉื ืืืื ืืืืืกื
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