Question

C语言串拷贝(strcpy)和内存拷贝(memcpy)函数有什么不同?

Answer 1

strcpy()函数只能拷贝字符串。strcpy()函数将源字符串的每个字节拷贝到目录字符串中，当遇到字符串末尾的null字符(\0)时，它会删去该字符，并结束拷贝。 memcpy()函数可以拷贝任意类型的数据。因为并不是所有的数据都以null字符结束，所以你要为memcpy()函数指定要拷贝的字节数。 在拷贝字符串时，通常都使用strcpy()函数；在拷贝其它数据(例如结构)时，通常都使用memcpy()函数。以下是一个使用strcpy()函数和memcpy()函数的例子： #include <stdio. h> #include <string. h> typedef struct cust-str {int id ;char last_name [20] ; char first_name[l5];} CUSTREC;void main (void); void main (void){char * src_string = "This is the source string" ; char dest_string[50]; CUSTREC src_cust; CUSTREC dest_cust; printf("Hello! I'm going to copy src_string into dest_string!\n"); / * Copy src_ string into dest-string. Notice that the destination string is the first argument. Notice also that the strcpy() function returns a pointer to the destination string. * / printf("Done! dest_string is: %s\n" , strcpy(dest_string, src_string)) ; printf("Encore! Let's copy one CUSTREC to another. \n") ; prinft("I'll copy src_cust into dest_cust. \n"); / * First, intialize the src_cust data members. * / src_cust. id = 1 ; strcpy(src_cust. last_name, "Strahan"); strcpy(src_cust. first_name, "Troy"); / * Now, Use the memcpy() function to copy the src-cust structure to the dest_cust structure. Notice that, just as with strcpy(), the destination comes first. * / memcpy(&dest_cust, &src_cust, sizeof(CUSTREC));