将 if 语句转换为 for 循环？

Question

我在 mikroC 中编写了一个函数，用于扫描 4x4 键盘中按下的按键

void scan_key()
{
    PORTB = 0B11111110;
    if ( PORTB == 0b11101110){
        Row = 1;
        Column = 1;
        return;
    }
    if ( PORTB == 0b11011110){
        Row = 2;
        Column = 1;
        return;
    }
    if ( PORTB == 0b10111110){
        Row = 3;
        Column = 1;
        return;
    }
    if ( PORTB == 0b01111110){
        Row = 4;
        Column = 1;
        return;
    }

    PORTB = 0B11111101;
    if ( PORTB == 0b11101101){
        Row = 1;
        Column = 2;
        return;
    }
    if ( PORTB == 0b11011101){
        Row = 2;
        Column = 2;
        return;
    }
    if ( PORTB == 0b10111101){
        Row = 3;
        Column = 2;
        return;
    }
    if ( PORTB == 0b01111101){
        Row = 4;
        Column = 2;
        return;
    }

    PORTB = 0B11111011;
    if ( PORTB == 0b11101011){
        Row = 1;
        Column = 3;
        return;
    }
    if ( PORTB == 0b11011011){
        Row = 2;
        Column = 3;
        return;
    }
    if ( PORTB == 0b10111011){
        Row = 3;
        Column = 3;
        return;
    }
    if ( PORTB == 0b01111011){
        Row = 4;
        Column = 3;
        return;
    }

    PORTB = 0B11110111;
    if ( PORTB == 0b11100111){
        Row = 1;
        Column = 4;
        return;
    }
    if ( PORTB == 0b11010111){
        Row = 2;
        Column = 4;
        return;
    }
    if ( PORTB == 0b10110111){
        Row = 3;
        Column = 4;
        return;
    }
    if ( PORTB == 0b01110111){
        Row = 4;
        Column = 4;
        return;
    }

    PORTB = 0B11110000;
}

有没有办法把这个算法转换成循环？

Answer 1

是的。 (至少假设您实际上并不打算在每个 if block 之前进行这些分配。我假设它们是为了测试？否则您的代码就没有意义。)

至少，您可以将每个二进制值放入一个数组中，并构造一个如下所示的循环:

int portValue[4][4] = {{0b11101110, 0b11011110, 0b10111110, 0b01111110}, {//...Rest of values here }}

int loop_col = 0;
int loop_row = 0;

for (loop_col = 0; loop_col < 4; loop_col++){
    for (loop_row = 0; loop_row < 4; loop_row++){
         if ( PORTB == portValue[loop_col][loop_row]){
             Row = loop_row + 1;
             Column = loop_col + 1;
             return;
         }
    }
}