The problem here is, for an input like abc XYZ the code scanf(“%s”,name); reads only the “abc” part and the “XYZ” is left in the input buffer. The later gets() read that, and puts() prints that. As you don’t have a newline after the printf(), the output is not flushed and the outcome of the … Read more
scanf returns the count of items that it has successfully read according to your format. You can set up a loop that exits only when scanf(“%d”, &number2); returns 1. The trick, however, is to ignore invalid data when scanf returns zero, so the code would look like this: while (scanf(“%d”,&number2) != 1) { // Tell … Read more
The scanf family of function cannot be used safely, especially when dealing with integers. The first case you mentioned is particularly troublesome. The standard says this: If this object does not have an appropriate type, or if the result of the conversion cannot be represented in the object, the behavior is undefined. Plain and simple. … Read more
The scanf function reads into a C string (actually an array of char), like this: char word[40]; int nChars = scanf(“%39s”, word); // read up to 39 chars (leave room for NUL) You can convert a char array into NSString like this: NSString* word2 = [NSString stringWithBytes:word length:nChars encoding:NSUTF8StringEncoding]; However scanf only works with console … Read more
Whitespace in the format string matches 0 or more whitespace characters in the input. So “%d c %d” expects number, then any amount of whitespace characters, then character c, then any amount of whitespace characters and another number at the end. “%dc%d” expects number, c, number. Also note, that if you use * in the … Read more
I wrote a bit of code that can read in string and character literals. Like normal stream reads, if it gets invalid data it sets the badbit of the stream. This should work for all types of streams, including wide streams. Stick this bit in a new header: #include <iostream> #include <string> #include <array> #include … Read more
scanf(“%s”, &me); should be scanf(“%s”, me); Explanation: “%s” means that scanf is expecting a pointer to the first element of a char array. me is an object array and could be evaluated as pointer. That’s why you can use me directly without adding &. Adding & to me will be evaluated to ‘char (*)[20]’ and … Read more
For those you need to use the macros from inttypes.h such as SCNd64 or SCNu32 etc. scanf(“%” SCNd32, &x);
For printf, the * allows you to specify the minimum field width through an extra parameter, e.g. printf(“%*d”, 4, 100); specifies a field width of 4. A field width of 4 means that if a number takes less than 4 characters to print, space characters are printed until the field width is filled. If the … Read more
They are declared in <inttypes.h> as macros: SCNd8, SCNd16, SCNd32 and SCNd64. Example (for int32_t): sscanf (line, “Value of integer: %” SCNd32 “\n”, &my_integer); Their format is PRI (for printf)/SCN (for scan) then o, u, x, X d, i for the corresponding specifier then nothing, LEAST, FAST, MAX then the size (obviously there is no … Read more