Подсчет количества топлива для первой ступени ракеты-носителя

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
enum
{
    no_change,
    mass_changed,
    coeff_changed
};
 
int GetMinMaxValue(const int value, int (*predicate)(const int, const int));
int more(const int a, const int b);
int less(const int a, const int b);
 
int main(void)
{
    int originalMass = 0;       /* user input */
    int originalCoeff = 0;      /* user input */
    int newMass = 0;            /* recalculated mass in case of input error */
    int newCoeff = 0;           /* recalculated flight coefficient in case of input error */
    int newFuelCount = 0;       /* recalculated fuel count in case of input error */
    int maxFuelCount = 0;       /* maximal fuel count calculated */
    int changeCode = no_change; /* error flag, marks what user input wrong if any */
    
    printf("Enter mass of the satellite (units) : ");
    scanf("%d", &originalMass);
    
    printf("Enter flight coefficient (units) : ");
    scanf("%d", &originalCoeff);
    
    /* calculating initial fuel count */
    maxFuelCount = originalMass - originalCoeff;
        
    /* trying mass increase */
    newMass = GetMinMaxValue(originalMass, more);
    
    newCoeff = originalCoeff;
    newFuelCount = newMass - newCoeff;
        
    if (newFuelCount > maxFuelCount)
    {
        maxFuelCount = newFuelCount;
        changeCode = mass_changed;
    }
    
    /* trying coefficient decrease */
    newCoeff = GetMinMaxValue(originalCoeff, less);
        
    newFuelCount = originalMass - newCoeff;
        
    if (newFuelCount > maxFuelCount)
    {
        maxFuelCount = newFuelCount;
        changeCode = coeff_changed;
    }
    
    if (changeCode == mass_changed)
    {
        printf("Maximal fuel : %d (mass [ERROR] = %d instead of %d, coeff [OK] = %d)\n",
            maxFuelCount, newMass, originalMass, originalCoeff);
    }
    else if (changeCode == coeff_changed)
    {
        printf("Maximal fuel : %d (mass [OK] = %d, coeff [ERROR] = %d instead of %d)\n",
            maxFuelCount, originalMass, newCoeff, originalCoeff);
    }
    else
    {
        printf("Maximal fuel : %d (mass [OK] = %d, coeff [OK] = %d)\n",
            maxFuelCount, originalMass, originalCoeff);
    }
    
    return 0;
}
 
int more(const int a, const int b)
{
    return a > b;
}
 
int less(const int a, const int b)
{
    return a < b;
}
 
int GetMinMaxValue(const int value, int (*predicate)(const int, const int))
{
    int minMax = value;
    int digitCount = 0;
    int i = 0;
    int startIndex = 0;
    int newValue = 0;
    
    char valueStr[32];
    char temp;
    
    if (abs(value) < 12)
    {
        return value;
    }
    
    if (value < 0) startIndex = 1;
    
    sprintf(valueStr, "%d", value);
    
    digitCount = strlen(valueStr);
    
    for (i = startIndex; i < digitCount - 1; i++)
    {
        temp = valueStr[i];
        valueStr[i] = valueStr[i + 1];
        valueStr[i + 1] = temp;
        
        sscanf(valueStr, "%d", &newValue);
        
        if (predicate(newValue, minMax)) minMax = newValue;
        
        temp = valueStr[i];
        valueStr[i] = valueStr[i + 1];
        valueStr[i + 1] = temp;
    }
    
    return minMax;
}