![]() ![]() The exponent always contains two digits if the value is zero, the exponent is 00. An E conversion uses the letter ‘E’ (rather than ’e’) to introduce the exponent. eE The double argument is rounded and converted in the format “d.ddde±dd” where there is one digit before the decimal-point character and the number of digits after it is equal to the precision if the precision is missing, it is taken as 6 if the precision is zero, no decimal-point character appears.If a precision is given, no null character need be present if the precision is not specified, or is greater than the size of the array, the array must contain a terminating NUL character. Characters from the array are written up to (but not including) a terminating NUL character if a precision is specified, no more than the number specified are written. s The “char *” argument is expected to be a pointer to an array of character type (pointer to a string).c The int argument is converted to an “unsigned char”, and the resulting character is written.p The void * argument is taken as an unsigned integer, and converted similarly as a %#x command would do.The precision, if any, gives the minimum number of digits that must appear if the converted value requires fewer digits, it is padded on the left with zeros. The letters “abcdef” are used for x conversions the letters “ABCDEF” are used for X conversions. diouxX The int (or appropriate variant) argument is converted to signed decimal (d and i), unsigned octal (o), unsigned decimal (u), or unsigned hexadecimal (x and X) notation.To setup the Uno properly for serial communications, the following elements have to part of your program (see highlighted lines below):Ī You entered the character a, 97 in ASCII decimal, 61 in ASCII hexī You entered the character b, 98 in ASCII decimal, 62 in ASCII hexġ You entered the character 1, 49 in ASCII decimal, 31 in ASCII hex For our purposes, the standard input and output stream will be the USB communications between the Uno and our computer. The concept of serial input/output (I/O) is to provide the capability to communicate to (input) the Uno and have the Uno communicate back (output) to the PC. There is considerable detail as to how to use printf below. printf(format, variable list): writes to the standard output stream, the list of variables using the formatting string specified.puts(string): print a null-terminated string to the standard output stream, ending with a newline character. ![]() putchar(char): writes a character to the standard output stream.getchar(): reads the next character from the standard input stream and returns it as type int.In order to communicate via the USB serial cable, you must run a serial monitor program such as the Arduino Serial Monitor, CoolTerm, or moserial. The serial input/output capabilities of C are vastly superior to those in the Arduino framework. Where I describe the functions for serial input/out - puts(), getchar() and printf(). ![]()
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