Tackling a Common Bug With scanf()

In legacy code and environments that support C exclusively, using scanf() is still a widespread method of getting input from a user (or a file, when using fscanf()). When using this function, beware of a common bug that results from C’s weak type-checking:

   #include   int main()  {    int n;    scanf("%d", n); /* a bug; should read '&n' */  }

The first parameter of scanf() is a format string that describes the type and length of the data to be read. The following arguments must be one ore more pointers to buffers into which the input is written. Unlike C++, C enforces weak type checks. Therefore, a C compiler doesn’t detect that the second argument passed to scanf() is an int rather than a pointer to int. Consequently, the program’s behavior is undefined?the input is written to a random memory address, not to n. The correct form should be:

   scanf("%d", &n); /* now OK */
Share the Post:
Share on facebook
Share on twitter
Share on linkedin


The Latest

microsoft careers

Top Careers at Microsoft

Microsoft has gained its position as one of the top companies in the world, and Microsoft careers are flourishing. This multinational company is efficiently developing popular software and computers with other consumer electronics. It is a dream come true for so many people to acquire a high paid, high-prestige job

your company's audio

4 Areas of Your Company Where Your Audio Really Matters

Your company probably relies on audio more than you realize. Whether you’re creating a spoken text message to a colleague or giving a speech, you want your audio to shine. Otherwise, you could cause avoidable friction points and potentially hurt your brand reputation. For example, let’s say you create a

chrome os developer mode

How to Turn on Chrome OS Developer Mode

Google’s Chrome OS is a popular operating system that is widely used on Chromebooks and other devices. While it is designed to be simple and user-friendly, there are times when users may want to access additional features and functionality. One way to do this is by turning on Chrome OS