Concat多个字符串？

Question

我有一个如下所示的行，但是我需要为目录连接斜杠，有没有办法安全地连接多个字符串？

// Need to include \\ after windowsDir
FILE *dest = fopen(strcat(windowsDir, filename),"wb");

Answer 1

char *buf = malloc(strlen(windowsDir) + 1 + strlen(filename) + 1); // len + \ + len + \0
sprintf(buf, "%s\\%s", windowsDir, filename);
FILE *dest = fopen(buf, "wb");
free(buf);

Answer 2

假设周围有足够的空间，这可行

strcpy(buff, "C:\\foobar");
strcpy(value, "file.txt");
strcat(strcat(buff, "\\"), value);
/* buff now has "C:\\foobar\\file.txt" */