The strcpy()
function in C++ copies a character string from source to destination. It is defined in the cstring header file.
Example
#include <cstring>
#include <iostream>
using namespace std;
int main() {
char src[] = "Hello Programmers.";
// large enough to store content of src
char dest[20];
// copy the contents of src to dest
strcpy(dest,src);
cout << dest;
return 0;
}
// Output: Hello Programmers.
strcpy() Syntax
The syntax of strcpy()
is:
strcpy( char* dest, const char* src );
strcpy() Parameters
The strcpy()
function takes the following parameters:
- dest - pointer to a C-string where the contents are copied to
- src - pointer to a C-string where the contents are copied from
strcpy() Return Value
The strcpy()
function returns:
- dest (the pointer to the destination C-string)
strcpy() Prototype
The prototype of strcpy()
as defined in the cstring header file is:
char* strcpy(char* dest, const char* src);
The strcpy()
function copies the C-string pointed to by src to the memory location pointed to by dest. The null terminating character '\0'
is also copied.
Notice that:
- src is of
const char*
type. Theconst
keyword ensures that the C-string pointed to by src cannot be modified bystrcpy()
. - dest is of
char*
type. The absence ofconst
ensures that the C-string pointed to by dest can be modified bystrcpy()
.
strcpy() Undefined Behavior
The behaviour of strcpy()
is undefined if:
- The memory allocated for dest pointer is not large enough.
- The strings overlap.
Example: C++ strcpy()
#include <cstring>
#include <iostream>
using namespace std;
int main() {
char src[20] = "I am the source.";
// large enough to store content of src
char dest[30] = "I am the destination.";
cout << "dest[] before copy: " << dest << endl;
// copy contents of src to dest
strcpy(dest,src);
cout << "dest[] after copy: " << dest;
return 0;
}
Output
dest[] before copy: I am the destination. dest[] after copy: I am the source.
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