Hello,
I am looking for a better way to do compares of multiple int values, returning the value with the highest (or lowest) values in an efficient manner. The way that I am doing it now is as follows:
This scans 3 different positions, and finds closest object-
if (dist_left < dist_right) {
if (dist_left < dist_center) {
driveit(500, 8); //rotate left 1/8
}
}
if (dist_right < dist_left) {
if (dist_right < dist_center) {
driveit(500, 7); //rotate right 1/8
}
}
if (dist_center < dist_right) {
if (dist_center < dist_left) {
if (dist_left < dist_right) {
driveit(500, 8); //rotate left 1/2
}
}
The problem with this is that if i want to add more scan ranges, this particular style of comparison gets incredibly complex. It seems to me that there is a much simpler way to do this, I just cant figure it out at the moment.
If you stored your distances in an integer array you could write a function that was passed a pointer to the array and the number of elements in the array. Your function could loop through all the elements and compare each to a highestValue variable (initially set to 0, and set to any value higher than itself). When you loop is finished with all the elements you can return highestValue .
int getHighestValue( int * elements, int count){
int highestValue = 0;
// your code that does the loop and compare goes here?.
return highestValue;
}
I would still want to know which integer was related to each scan point, so to play with that idea a bit:
char sparray [10]; //name of scanpoint
int spvarray [10]; //value of scanpoint
//code for setup
sparray[1]=sp1; //etc to fill array with the 10 scanpoints
//code during data acquisition
spvarray[1]=scanrange(); //etc to fill array with the 10 scanpoint values
//code during object avoidance
nearestobj = (sparray[getHighestValue(spvarray, 10)]) //finds scanpoint with highest value
//direction decision code goes here
int getHighestValue ( int * sparray, int count){
int highestValue = 0;
int count1 = 0;
if (count1 < count) {
if (sparray[count1] > highestValue) {highestValue = count1}
count1++
}
I think I am borking something up in the above, just typing it here and not in the arduino environment, and am still new to this.
Does that look like it would work? I need to play with arrays more...
Thanks!
I have not tested it but I hope this gets you closer to what you want:
char * spNames[10] = {"item0","item1","item2","item3","item4","item5","item6","item7","item8", "item9"}; //name of scanpoint
int spvarray [10]; //value of scanpoint
long randNumber;
void setup(){
Serial.begin(9600);
for(int i=0; i < 10; i++){
spvarray[i] = (int)random(1000); //etc to fill array with the 10 scanpoints with random numbers between 0 and 1000
Serial.print(i,DEC);
Serial.print("=");
Serial.println(spvarray[i],DEC); // display the values on the serial terminal
}
}
void loop() {
int nearestobj = getHighestValue(spvarray, 10); //finds scanpoint with highest value
Serial.print("nearest object is ");
Serial.println( spNames[nearestobj]); //finds scanpoint with highest value
delay(5000);
}
// this function returns the index of the highest value in the given array
int getHighestValue( int * array, int count){
int highestValueIndex = 0;
for(int i=1; i < count; i++){
if (array[i] > array[highestValueIndex] )
highestValueIndex = i;
}
return highestValueIndex;
}
Thank you very much
This is great - this logic should get me right where I want to be, and allow me to extend it much easier than I thought I would be able to.
/bow to the code guru!
