Convert if statements to for loop? [closed]
문제
I've written a function in mikroC that scan the pressed key in a 4x4 keypad
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;
}
Is there a way to convert this algorithm into a loop?
해결책
Yes. (At least assuming you don't actually mean to have those assignments before each block of if
s. I assume they were there for testing? otherwise your code doesn't make sense.)
At the very least, you can put each of the binary values into an array, and construct a loop like this:
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;
}
}
}
다른 팁
Yes of course.
First do some array with your values. we'll call it t[] and second is d[][] // two dimensional array
and lets do double loop
for(i=1;i<=4;i++)
{
cur_value=t[i]; // our value
for(j=1;j<=4;j++)
{
right_side_value=d[i][j];
if(cur_value==right_side_value)
{
rows=i;
columns=j;
return;
}
}
}
Hope that helps.
Don't know if 1 dimensional array is only needed for d values, didnt check every number
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