#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define SIZE_OF_ARRAY 100
#define LINE_SIZE 2

int main()
{
    float result_of_main;
    float x,a,b,c;
    int result=reading_input(&x);
    if(result==0){
        printf("x");
        return 0;
    }
    result=reading_input(&a);
    if(result==0){
        printf("a");
        return 0;
    }
    result=reading_input(&b);
    if(result==0){
        printf("b");
        return 0;
    }
    result=reading_input(&c);
    if(result==0){
        printf("c");
        return 0;
    }
    result_of_main=a*(x*x)+b*x+c;

    printf("Vysledok je: %.2f", result_of_main);
    return 0;
}
int reading_input(float *number){
    char buffer[SIZE_OF_ARRAY];
    fgets(buffer,SIZE_OF_ARRAY,stdin);
    for(int j=0; buffer[j]!='\0'; j++){
        if (buffer[j]>='0'&&buffer[j]<='9') {
            continue;
        }
        if (buffer[j]=='.'||buffer) {
            continue;
        }
        if(buffer[j]=='\n'){
            buffer[j]='\0';
            break;
        }
        printf("You have entered wrong number.\n");
        return 0;
    }
    *number=atof(buffer);
    return 1;
}