C51中的printf函数
keil→Help→μVision Help→C51 Development Tools→Cx51 Compiler Users' Guide→Library Reference→Include Files→stdio.h→printf
通过以上路径可以找到Keil C51帮助手册中printf函数的信息。
函数原型：
1 2 3 4 5 | #include <stdio.h> int printf ( const char *fmtstr /* format string */ <[>, arguments ... <]>); /* additional arguments */ |
printf函数使用putchar函数构建一个字符串并写入输出流。
fmtstr是一个格式参数，可以由字符，转义序列和格式字符串组成。
格式字符串的格式为
1 | % <[>flags<]> <[>width<]> <[>.precision<]> <[>{b|B|l|L}<]> type |
| Type | Argument Type | Input Format | 描述 |
|---|---|---|---|
| d | int | Signed decimal number | 有符号整型数 |
| u | unsigned int | Unsigned decimal number | 是 |
| o | unsigned int | Unsigned octal number | 无符号八进制数 |
| x | unsigned int | Unsigned hexadecimal number using "0123456789abcedf" | 无符号十六进制数 |
| X | unsigned int | Unsigned hexadecimal number using "0123456789ABCDEF" | 无符号十六进制数 |
| f | float | Floating-point number formatted as<[>-<]>dddd.dddd. | float浮点型 |
| e | float | Floating-point number formatted as <[>-<]>d.dddde<[>-<]>dd | float浮点型 |
| E | float | Floating-point number formatted as <[>-<]>d.ddddE<[>-<]>dd. | float浮点型 |
| g | float | Floating-point number using either the e or f format, whichever is more compact for the specified value and precision. | 数 |
| G | float | Floating-point number using either the E or f format, whichever is more compact for the specified value and precision. | 数 |
| c | char | A single character | 单一字符 |
| s | * | A string of characters terminated by a null character (' ') | 字符串 |
| p | * | A generic pointer formatted as t:aaaa where t is the memory type and aaaa is the hexadecimal address | 指针 |