> For the complete documentation index, see [llms.txt](https://wenbo-notes.gitbook.io/cs1010-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wenbo-notes.gitbook.io/cs1010-notes/lec-tut-lab-exes/lecture/lec-11-strcut-and-standard-i-o/diagnostic-quiz.md).

# Diagnostic Quiz

## Problems

### 5. printf() behavior

```c
printf("%.2f", 41); // This will print 0.0 and generates a warning
```

### 7. scanf() and fgets()

To read in a 6-letter module code (e.g., "CS1010") from the standard input? We can use

```c
char module_code[7];
scanf("%6s", module_code);
// or
char module_code[7];
fgets(module_code, 7, stdin);
```

### 8. Output Analysis

{% code lineNumbers="true" %}

```c
long x;
scanf("%ld", &x);
printf("You entered %ld\n", x);
scanf("%ld", &x);
printf("You entered %ld\n", x);
```

{% endcode %}

If the input is a floating point number, the first `scanf()` at Line 2 will consume the number **in front of the floating point** and store it in the variable `x`. And the `scanf()` at Line 4 will read nothing because `.`(char) doesn't match with `%ld`(long), so `x` will still be the same number and is printed out again.