#include <stdio.h>
#define MAX 100

int isPrime(int n) {
    if(n < 2) return 0;
    for(int i = 2; i <= n/2; i++)
        if(n % i == 0) return 0;
    return 1;
}

int main() {
    int n, choice;
    float a[MAX];

    printf("Enter n: ");
    scanf("%d", &n);

    printf("Enter array:\n");
    for(int i = 0; i < n; i++) {
        scanf("%f", &a[i]);
    }

    do {
        printf("\n----- MENU -----\n");
        printf("1. Input array\n");
        printf("2. Print array\n");
        printf("3. Average\n");
        printf("4. Sum positive\n");
        printf("5. Reverse array\n");
        printf("6. Check symmetric\n");
        printf("7. Check increasing\n");
        printf("8. Max even\n");
        printf("9. Delete value x\n");
        printf("0. Exit\n");

        printf("Choose: ");
        scanf("%d", &choice);

        if(choice == 1) {
            printf("Re-enter array:\n");
            for(int i = 0; i < n; i++) {
                scanf("%f", &a[i]);
            }
        }

        else if(choice == 2) {
            for(int i = 0; i < n; i++)
                printf("%.2f ", a[i]);
            printf("\n");
        }

        else if(choice == 3) {
            float sum = 0;
            for(int i = 0; i < n; i++) sum += a[i];
            printf("Average = %.2f\n", sum/n);
        }

        else if(choice == 4) {
            float sum = 0;
            for(int i = 0; i < n; i++)
                if(a[i] > 0) sum += a[i];
            printf("Sum positive = %.2f\n", sum);
        }

        else if(choice == 5) {
            for(int i = 0; i < n/2; i++) {
                float t = a[i];
                a[i] = a[n-1-i];
                a[n-1-i] = t;
            }
            printf("Reversed!\n");
        }

        else if(choice == 6) {
            int ok = 1;
            for(int i = 0; i < n/2; i++)
                if(a[i] != a[n-1-i]) ok = 0;

            if(ok) printf("Symmetric\n");
            else printf("Not symmetric\n");
        }

        else if(choice == 7) {
            int ok = 1;
            for(int i = 1; i < n; i++)
                if(a[i] < a[i-1]) ok = 0;

            if(ok) printf("Increasing\n");
            else printf("Not increasing\n");
        }

        else if(choice == 8) {
            int found = 0;
            int max = -1;

            for(int i = 0; i < n; i++) {
                if((int)a[i] % 2 == 0) {
                    if(!found || a[i] > max) {
                        max = (int)a[i];
                        found = 1;
                    }
                }
            }

            if(found) printf("Max even = %d\n", max);
            else printf("No even number\n");
        }

        else if(choice == 9) {
            float x;
            printf("Enter x: ");
            scanf("%f", &x);

            int k = 0;
            for(int i = 0; i < n; i++) {
                if(a[i] != x) {
                    a[k++] = a[i];
                }
            }
            n = k;
            printf("Deleted!\n");
        }

    } while(choice != 0);

    return 0;
}