Student1492259.c

// De Thi 1
// 15.08.2023

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

#define MAX 20

struct City
{
    char areaCode[30];
    char name[30];
    int population;
};
struct City c[MAX];

int numberOfCitiesInput;

void inputCity(struct City[]);
void outputCity(struct City[]);

void doQuestionR1()
{
    // Check whether a number is PRIME or not
    puts("Checking the prime:");
    int n;
    printf("Enter a number: ");
    scanf("%d", &n);

    if (n == 0 || n == 1)
    {
        puts("This is NOT a prime");
        return;
    }
    if (n == 2)
    {
        puts("This is a prime");
        return;
    }

    for (int i = 2; i < n; i++)
    {
        if (n % i == 0)
        {
            puts("This is NOT a prime");
            break;
        }
        else
        {
            puts("This is a prime");
            break;
        }
    }

    puts("-END OF R1-");
    return;
}

void doQuestionR2()
{
    printf("Enter the number of cities: ");
    scanf("%d", &numberOfCitiesInput);

    inputCity(c);
    outputCity(c);

    return;
}

void inputCity(struct City c[])
{
    for (int i = 0; i < numberOfCitiesInput; i++)
    {
        printf("Input for city %d: \n", i + 1);

        printf("\t - Code: ");
        scanf(" %[^\n]", c[i].areaCode);

        printf("\t - Name: ");
        scanf(" %[^\n]", c[i].name);

        printf("\t - Population: ");
        scanf("%d", &c[i].population);

        printf("\n");
    }
}

void outputCity(struct City c[])
{
    int maxIndex = 0;
    int maxValue = 0;

    puts("------------------------------");
    puts("Displaying all cities:");
    puts("------------------------------");
    for (int i = 0; i < numberOfCitiesInput; i++)
    {
        printf("City %d:", i + 1);
        printf("\t Code: %s \n", c[i].areaCode);
        printf("\t Name: %s \n", c[i].name);
        printf("\t Population: %d \n\n", c[i].population);

        // So sanh Max
        if (c[i].population > maxValue)
        {
            maxIndex = i;
            maxValue = c[i].population;
        }
    }

    puts("------------------------------");
    puts("City's most populous:");
    puts("------------------------------");
    printf("\t Code: %s \n", c[maxIndex].areaCode);
    printf("\t Name: %s \n", c[maxIndex].name);
    printf("\t Population: %d \n\n", c[maxIndex].population);

    puts("-END OF R2-");
}

void doQuestionR3()
{
    puts("Exit program....");
    exit(0);
}

void menu()
{
    puts("*********************************");
    puts("* Select Action:                *");
    puts("* \t 1. R1 \t\t\t*");
    puts("* \t 2. R2 \t\t\t*");
    puts("* \t 3. R3 \t\t\t*");
    puts("*********************************");
}

int main()
{
    int choice;

    do
    {
        menu();
        printf("Option: ");
        scanf("%d", &choice);

        // clear screen
        printf("\033[H\033[2J");

        // Choice into programs:
        switch (choice)
        {
        case 1:
            doQuestionR1();
            break;
        case 2:
            doQuestionR2();
            break;
        case 3:
            doQuestionR3();
            break;

        default:
            // clear screen
            printf("\033[H\033[2J");

            puts("\n\t INVALID! Please choose from 1 2 or 3.");
            continue;
        }

    } while (1);

    return 0;
}