C語言編程：.H文件與.C文件的關(guān)系！

/*如下為鍵盤驅(qū)動的頭文檔*/#ifndef _KEY_H_ //防重復(fù)引用，如果沒有定義過_KEY_H_，則編譯下句#define _KEY_H_ //此符號唯一， 表示只要引用過一次，即#i nclude，則定義符號_KEY_H_/////////////////////////////////////////////////////////////////char keyhit( void ); //擊鍵否unsigned char Keyscan( void ); //取鍵值////////////////////////////////////////////////////////////////#endif

#define KEYNUM 65//按鍵數(shù)量，用于Keycode[KEYNUM]#define LINENUM 8//鍵盤行數(shù)#define ROWNUM 8//鍵盤列數(shù)

static unsigned char sts;//按鍵狀態(tài)變量static unsigned char Nowkeycode;//此時的鍵碼static unsigned char Prekeycode;//上一次的鍵碼static unsigned char Keydowntime;//矩形鍵盤按下去抖時間變量static unsigned char Keyuptime;//矩形鍵盤釋放去抖時間變量static unsigned char Onoffdowntime;//關(guān)機(jī)鍵按下去抖時間變量static unsigned char Onoffuptime;//關(guān)機(jī)鍵釋放去抖時間變量static unsigned char onoff_10ms; //判斷關(guān)機(jī)鍵中斷次數(shù)變量，累計150次大約為3S,因為前后進(jìn)了兩個10ms中斷

const unsigned char a=1;//定義a=1，編譯器不允許修改a的值作用：保護(hù)不希望被修改的參數(shù)const unsigned char Key_code[KEYNUM]={0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,0x40,0x41};//鍵碼const unsigned char Line_out[LINENUM]={0xFE,0xFD,0xFB,0xf7,0xEF,0xDF,0xBF,0x7F};//行輸出編碼const unsigned char Row_in[ROWNUM]={0xFE,0xFD,0xFB,0xf7,0xEF,0xDF,0xBF,0x7F};//列輸入編碼

static int i=0;int main(void){...while (1){if (i)dosomething();}}/* Interrupt service routine. */void ISR_2(void){i=1;}