Functions in C string. h

1. # include <string. h>

Void * memcpy (void * To, const void * From, size_t count );

Function:FromCopyingCountCharactersToAnd returnToPointer. IfToAndFromOtherwise, the function behavior is uncertain.

 

Note: (1) the first parameter is the target pointer, and the second parameter is the starting pointer. Do not make a mistake.

(2) During the copy process, the unit of counting is characters, that is, bytes.

Example:

# Include <iostream>
# Include <cstring>
Using namespace STD;

Int main (){
 
Int A [4] = {1, 2, 4 };
Int B [4];
Memcpy (B, A, 4*4); // copy the one-dimensional int Array
 
For (INT I = 0; I <sizeof (B)/4; I ++)
Cout <B [I] <"";

Cout <Endl;
 
Int C [2] [2] = {1, 2, 3, 4}; // copy the two-dimensional int Array
Int d [2] [2];
Memcpy (D, C, 4*4 );
For (INT I = 0; I <2; I ++ ){
For (Int J = 0; j <2; j ++)
Cout <D [I] [J] <"";
Cout <Endl;
}
 
Char E [2] [2] = {'A', 'B', 'C', 'D'}; // copy a two-dimensional char array
Char f [2] [2];
Memcpy (F, E, 4 );
For (INT I = 0; I <2; I ++ ){
For (Int J = 0; j <2; j ++)
Cout <F [I] [J] <"";
Cout <Endl;
}

}

 

 

Another example program:

Struct map {
 
Int;
String B;
};

Int main (){
 
Struct map a [2] = {4, "hello"}, {1, "world" }}, B [2];
Memcpy (B, A, sizeof (MAP) * 2 );
Cout <B [0]. B <Endl;
}

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