positioning a servo-if else loops

[PBYGuk]

hello. my project is such- i have a flat surface fitted with sensors and i need to move the surface with the help of the servo such that the sensor reading gives me zero value. however when i run the following codes, the servo does not stop at the condition when sensor is zero. for example if i have sensor greater than reference (0), the servo performs the task well of decreasing the value of the sensor but instead of stopping at sensor=zero it keeps moving in the same direction hence incrementing the sensor in the negative direction. what is wrong with my codes please?

AnalogIn V_strain(p15);
 
 int main(){
 int reference=0;  
 float pg=3.3*V_strain;
 
while(1)
{ 
 float x=Servo1.read();
        
        Serial pc(USBTX, USBRX); // tx, rx
        pc.printf("%f\r\n",pg);
        
        if (V_strain>reference){
                do
                {
                x=x+10;   
                Servo1.write(x);
                }while(V_strain>reference);
                   
            }
            else if(V_strain<reference){       
                do 
                {      
                x=x-10;
                Servo1.write(x);
                }while(V_strain<reference);  
                            
                }

[ResidentBiscuit]

Hard to tell without knowing what AnalogIn is.

Your loops are weird, can this not be simplified by:

while(V_strain > reference)
{
    x = x + 10;
    Servo1.write(x);
}
while(V_strain < reference)
{
    x = x - 10;
    Servo1.write(x);
}

Anyways, I don't see where V_strain is ever changing, so why would it ever leave this loop?

[PBYGuk]

thanks for the reply. infact my main problem is that for each increase or decrease in the servo position, i constantly need to check the V_strain from the analog input pin until the condition is satisfied. another problem with the codes i am using is that i may cross the reference my incrementing the servo position by 10us, that is the reference may never be reached. I do not know very well how to put all these in codes since c++ is very new to me. Thanks for any help!