[PIC]Calculation Problem

int main2 (unsigned int a[]); //function to get array largest element position

sbit LCD_RS at RD4_bit;
sbit LCD_EN at RD5_bit;
sbit LCD_D4 at RD0_bit;
sbit LCD_D5 at RD1_bit;
sbit LCD_D6 at RD2_bit;
sbit LCD_D7 at RD3_bit;

sbit LCD_RS_Direction at TRISD4_bit;
sbit LCD_EN_Direction at TRISD5_bit;
sbit LCD_D4_Direction at TRISD0_bit;
sbit LCD_D5_Direction at TRISD1_bit;
sbit LCD_D6_Direction at TRISD2_bit;
sbit LCD_D7_Direction at TRISD3_bit;

unsigned int DataA[3] = {9,2,3};
unsigned int DataB[3]=  {1,9,3};
unsigned int DataC[3]=  {1,2,9};

float Time[3]= {0.2,0.4,0.8};

float ta,tb,tc;
int index;
float V1,tab1,tcb1,L1=1.00,X1;
char txt[15];


void main() {

    PORTA = 0;
    TRISA = 0X01;
    TRISB =0 ;
    PORTB = 0;
    TRISD =0 ;
    PORTD = 0;

    LCD_Init();
    LCD_Cmd(_LCD_CURSOR_OFF);
    LCD_Cmd(_LCD_CLEAR);
    LCD_Out(1, 1, "ANSWER:");

      index = main2(DataA); //get DataA max element position
      ta = Time[index];       // use the position to get data from Time
      index = main2(DataB);
      tb = Time[index];
      index = main2(DataC);
      tc = Time[index];

      tab1 = ta-tb;  
      tcb1 = tc-tb;

      delay_ms(200);

                      
         ///for calculation
         if(tab1 < tcb1){
         V1 = (float)1/(2*tcb1);
         X1 = 0.5*( (V1*tab1)+ (0.5*1) );
         }

         else if(tab1 > tcb1){
         V1 = (float)1/(2*tab1);
         X1 = (1-0.5)*( (V1*tab1)+ (0.5*1) );
         }

         FloatToStr(X1, txt);
         delay_ms(500);
         LCD_Out(2,1,txt);

      while (1){}  
}


int main2 (unsigned int a[]){
 int pos;
 unsigned int c;
 unsigned int maximum = a[0];
 unsigned int x;

  for (c = 1; c < 3; c++)
  {
    x = a[c];
    if ( x > maximum)
    {
       maximum  = a[c];
       pos = c;
    }
  }
  
 return pos;
}

FloatToStr(tcb1, txt);
delay_ms(500);
LCD_Out(2,1,txt);

 if(tab1 < tcb1){
         V1 = (float)1/(2*1);              //V1 = (float)1/(2*tcb1);  tcb1 changed to 1
         X1 = 0.5*( (V1*1)+ (0.5*1) );// X1 = 0.5*( (V1*tab1)+ (0.5*1) ); 
         }

         else if(tab1 > tcb1){
         V1 = (float)1/(2*1);                      //V1 = (float)1/(2*tcb1);
         X1 = (1-0.5)*( (V1*1)+ (0.5*1) );  // X1 = (1-0.5)*( (V1*tab1)+ (0.5*1) );
         }