scanf Type Field Characters
The type character is the only required format field; it appears after any optional format fields. The type character determines whether the associated argument is interpreted as a character, string, or number.
Table R.8 Type Characters for scanf functions
| Character | Type of Input Expected | Type of Argument |
| c | When used with scanf functions, specifies single-byte character; when used with wscanf functions, specifies wide character. White-space characters that are ordinarily skipped are read when c is specified. To read next non–white-space single-byte character, use %1s; to read next non–white-space wide character, use %1ws. | Pointer to char when used with scanf functions, pointer to wchar_t when used with wscanf functions. |
| C | When used with scanf functions, specifies wide character; when used with wscanf functions, specifies single-byte character. White-space characters that are ordinarily skipped are read when C is specified. To read next non–white-space single-byte character, use %1s; to read next non–white-space wide character, use %1ws. | Pointer to wchar_t when used with scanf functions, pointer to char when used with wscanf functions. |
| d | Decimal integer. | Pointer to int. |
| i | Decimal, hexadecimal, or octal integer. | Pointer to int. |
| o | Octal integer. | Pointer to int. |
| u | Unsigned decimal integer. | Pointer to unsigned int. |
| x | Hexadecimal integer. | Pointer to int. |
| e, E, f, g, G | Floating-point value consisting of optional sign (+ or –), series of one or more decimal digits containing decimal point, and optional exponent (“e” or “E”) followed by an optionally signed integer value. | Pointer to float. |
| n | No input read from stream or buffer. | Pointer to int, into which is stored number of characters successfully read from stream or buffer up to that point in current call to scanf functions or wscanf functions. |
| s | String, up to first white-space character (space, tab or newline). To read strings not delimited by space characters, use set of square brackets ([ ]), as discussed following Table R.7. | When used with scanf functions, signifies single-byte character array; when used with wscanf functions, signifies wide-character array. In either case, character array must be large enough for input field plus terminating null character, which is automatically appended. |
| S | String, up to first white-space character (space, tab or newline). To read strings not delimited by space characters, use set of square brackets ([ ]), as discussed preceding this table. | When used with scanf functions, signifies wide-character array; when used with wscanf functions, signifies single-byte–character array. In either case, character array must be large enough for input field plus terminating null character, which is automatically appended. |
The types c, C, s, and S are Microsoft extensions and are not ANSI-compatible.
Thus, to read single-byte or wide characters with scanf functions and wscanf functions**,** use format specifiers as follows.
| To Read Character As | Use This Function | With These Format Specifiers |
| single byte | scanf functions | c, hc, or hC |
| single byte | wscanf functions | C, hc, or hC |
| wide | wscanf functions | c, lc, or lC |
| wide | scanf functions | C, lc, or lC |
To scan strings with scanf functions, and wscanf functions**,** use the prefixes h and l analogously with format type-specifiers s and S.