if else convert to case problem

[ruben91]

[PIC] if else convert to case problem

i have some difficulties i converting if else to switch statement
pls help me with this, is it posibble to use variable case?

if(distance>=0 && distance<=250)
{
LATDbits.LATD0=1;
}

else if(distance>=251 && distance<=500)
{
LATDbits.LATD0=1;
Delay10KTCYx(25);
LATDbits.LATD0=0;
}

else if (distance>=501 && distance<=1000)
{
LATDbits.LATD0=1;
Delay10KTCYx(25);
Delay10KTCYx(25);
Delay10KTCYx(25);
LATDbits.LATD0=0;
}

else
{
}

 

[FvM]

Switch statement doesn't make much sense here. You can however omit redundant conditions.

---

Code C - [expand]
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if(distance>=0 && distance<=250)
...
else if(distance<=500)
...
else if (distance<=1000)
...
else

---

If distance is an unsigned quantity, >= 0 is also redundant (and hopefully already removed by the compiler).

 

[kam1787]

If distance can be negative then the code suggested by FvM isn't quite the same.

no you can not use a variable case.


assuming distance is >= zero...............

If you insisted you could divide distance by 250, though it is not quite the same

int dis

dis = distance / 250;

switch ( dis )
{
    case 0 : ........................ break    /* distance values of 0 to 249 */
    case 1:  .........................break    /* distance values of 250 to 499 */
    case 2:                                       /* distance values of 500 to 1000 */
    case 3:
    case 4: ...........................break
    
etc
}

- - - Updated - - -

or ..............faster though not the same break points

dis = distance >> 8 /* divide by 256 */

 

[FvM]

If distance can be negative then the code suggested by FvM isn't quite the same.

True indeed, so we would use this construct to avoid redundancies.

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Code C - [expand]
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if (distance < 0)
...
else if(distance<=250)
...
else if(distance<=500)
...
else if (distance<=1000)
...
else

---