在单片机中，用三个独立按键控制4种流水灯循环样式

可以使用状态机来实现这个功能。首先定义4种状态，分别对应4种流水灯循环样式。然后在每个状态下，根据按键的输入来决定下一个状态。具体实现可以使用if语句或者switch语句。以下是一个简单的示例代码：

#include <reg52.h>

#define KEY1 P1_0
#define KEY2 P1_1
#define KEY3 P1_2
#define LED P0

typedef enum {
    STATE_1,
    STATE_2,
    STATE_3,
    STATE_4
} State;

void delay(unsigned int ms) {
    unsigned int i, j;
    for (i = 0; i < ms; i++) {
        for (j = 0; j < 125; j++);
    }
}

void main() {
    State state = STATE_1;
    while (1) {
        switch (state) {
            case STATE_1:
                LED = 0x01;
                if (KEY1) {
                    state = STATE_2;
                } else if (KEY2) {
                    state = STATE_3;
                } else if (KEY3) {
                    state = STATE_4;
                }
                break;
            case STATE_2:
                LED = 0x03;
                if (KEY1) {
                    state = STATE_3;
                } else if (KEY2) {
                    state = STATE_4;
                } else if (KEY3) {
                    state = STATE_1;
                }
                break;
            case STATE_3:
                LED = 0x07;
                if (KEY1) {
                    state = STATE_4;
                } else if (KEY2) {
                    state = STATE_1;
                } else if (KEY3) {
                    state = STATE_2;
                }
                break;
            case STATE_4:
                LED = 0x0f;
                if (KEY1) {
                    state = STATE_1;
                } else if (KEY2) {
                    state = STATE_2;
                } else if (KEY3) {
                    state = STATE_3;
                }
                break;
        }
        delay(100);
    }
}

这个代码使用P1_0、P1_1、P1_2三个引脚作为按键输入，P0口作为LED输出。在每个状态下，根据按键的输入来决定下一个状态，从而实现4种流水灯循环样式的切换。