Question

im trying to change a part of a string using another pointer.
what I have

    char** string = (char**) malloc (sizeof(char*));
*string = (char*) malloc (100);
*string = "trololol";

char* stringP = *string;
stringP += 3;
stringP = "ABC";
printf("original string : %s\n\n", *string);
printf("stringP : %s\n\n", stringP);

What I get

original string : trololol;
stringP : ABC;

what I whant is troABCol in both of them 😀

I know I have a pointer to a string (char**) because thats what I need in order to do this operation inside a method.

Answer 1

you need to do strcpy(*string, "trololol") instead of *string = "trololol";. Your solution brings memory leak, as it replaces the memory pointer allocated by malloc() with pointer to data, which contains the pre-allocated “trololol” string.

strcpy() copies the pure string pointed to, and instead of stringP = "ABC";, you can do memcpy(stringP, "ABC", 3) (strcpy appends \0 at the end, whereas memcpy copies only data it is told to copy).