Определить, через сколько месяцев цена покупки увеличится более чем вдвое - C (СИ)

#include <stdio.h>
#define PERIOD 37
 
 
int main ( void )
{
    
    float patatoesPrice = 1.5, milkPrice = 0.7, eggsPrice = 0.5;
    unsigned char counter, months = 0;
    unsigned char doublePricePatatoes = 0, doublePriceMilk = 0, doublePriceEggs = 0;
    unsigned char firstSentinel = 0, secondSentinel = 0, thirdSentinel = 0;
    
    printf("%s%22s%22s%26s\n","Month","Price of patatoes","Price of milk","Price of eggs");
    puts("");
 
    
    for ( counter = 1; counter <= PERIOD; ++counter) {
        printf( "%-2d%25.2f%22.2f%26.2f", months++, patatoesPrice, milkPrice, eggsPrice);
        puts("");
        patatoesPrice *= 1.3;
        milkPrice *= 1.4;
        eggsPrice *= 2;
        if ( patatoesPrice >= (1.5 * 2) && firstSentinel < 1){
            doublePricePatatoes = months;
            ++firstSentinel;
            }
        if ( milkPrice >= (0.7 * 2) && secondSentinel < 1){
            doublePriceMilk = months;
            ++secondSentinel;
            }
        if ( eggsPrice >= (0.5 * 2) && thirdSentinel < 1){
            doublePriceEggs = months;
            ++thirdSentinel;
        }
    }
    
 
    printf("%s%d%s\n","Patato price become double after ",doublePricePatatoes," months");
    printf("%s%d%s\n","Milk price become double after ",doublePriceMilk," months");
    printf("%s%d%s\n","Eggs price become double after ",doublePriceEggs," months");
    return 0;
}