The strcpy function is a string copy function in the C standard library that is used to copy the source string to the target string. Overwrites the original target string contents
The function is defined as follows:
char *strcpy(char *dest, const char *src);
dest: A pointer to the target string, which needs to have enough space to accommodate the source string and the ending character 0.
src: The pointer to the source string to be copied.
When strcpy(dest, src) is called, the string pointed to by src is copied character by character to the memory area that dest points to until the terminator 0 is encountered. This means that if there is content that precedes the target string dest, it will be overwritten by the new source string content after the strcpy is executed.
Example: char str1 ="hello, world!";
char str2 = "goodbye, world!";
strcpy(str1, str2);
printf("%s", str1);Output: goodbye, world!
Pay attention to safety issues:
If the target buffer is not large enough to accommodate the source string, including the terminator, then strcpy can lead to a buffer overflow, which is a serious security vulnerability.
In practice, in order to prevent buffer overflows, it is often recommended to use a safer alternative function such as strncpy or strlcpy (not a standard C library function, but available in some system libraries), and to ensure that the target buffer size is handled correctly.