Memcpy vs. =

[mjbauer95]

What is the difference between memcpy() and just using the = symbol, as in:

char * str1;
str1 = "TEST.";
char * str2;
str2 = str1;

vs.

char * str1;
str1 = "TEST.";
char * str2;
strcpy(str2,str1);

What are the advantages of using strcpy because that seems to be the "right" way?

[whodgson]

char * str1; //str1 is a pointer of type char
str1 = "TEST."; //str1 is assigned "TEST" or is initialised to "TEST"
char * str2; //str2 is a pointer of type char
str2 = str1; str2 is assigned str1
vs.

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 char * str1; //same as above
str1 = "TEST."; //same as above
char * str2; //same as above
strcpy(str2,str1);//copy str1 into str2

memcpy() copies whats in memory at a specified location to another specified location in memory.

[santoshmp]

str2 = str1 simply assigns whatever address is there in str1 to str2.

memcpy and strcpy is almost the same in that it copies the contents of the memory pointed to by str2 to memory pointed to by str1. For memcpy you specify the number of bytes to be copied. strcpy on the other hand will copy all the contents till it finds a NULL character.

In you example, using strcpy or memcpy is not correct because str2 does not point to any memory allocation. It is pointing to some random location and so will cause a crash.

[donbock]

str2 = str1 simply assigns whatever address is there in str1 to str2.

Which means that str1 and str2 point to the same memory locations.

    str2[0] = 'T';
    str1[0] = 'A';
    if (str2[0] == 'T')
        ...
    else
        ...

The else-branch will be taken.