#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

int main() {
    setvbuf(stdin, NULL, _IONBF, 0);
    setvbuf(stdout, NULL, _IONBF, 0);

    srand(time(NULL));
    
    unsigned int i;
    int j =  rand() % 12345678 * -1;
    int r = j + 0;
    unsigned int input[5];
    char line[256];

    printf("\nWelcome to my calculator!\n");
    printf("Unfortunately, I only know how to do addition 5 times :(\n");
    printf("A prize will be given if you can make the number become my secret number!\n\n");
    
    for (i = 0; i < 5; i ++) {
        printf("Type in a number: ");

        if (fgets(line, sizeof(line), stdin)) {
            if (1 != sscanf(line, "%d", &input[i])) {
                line[strcspn(line, "\n")] = 0;
                printf(line);
                printf(" is not a valid number!\n\n");
                i --;
            } else {
                input[i] = abs(input[i]);
            }
        }
    }


    if (r == (input[0] + input[1] + input[2] + input[3] + input[4])) {
        printf("\nHere is your prize GCTF{%s}!\n","");
        return 0;
    } else {
        printf("\nYour sum: %d + %d + %d + %d + %d = %d\n", input[0], input[1], input[2], input[3], input[4], (input[0] + input[1] + input[2] + input[3] + input[4]));
        printf("\nMy secret is %d", r);
        return 1;
    }
}