Code:
#include <stdio.h>


typedef struct{
    
    char city[50];
    float celcius;
    float fahrenheit;
}Temperature;


int main()
{
    Temperature array[5];
    int i;
    float average1, average2, sum;
    
    for(i=0;i<5;i++)
    {
        printf("Insert a city: ");
        gets(array[i].city);
        fflush(stdin);
    }
    
    for(i=0;i<5;i++)
    {        
        printf("Insert the respective temperatures in celsius degrees: ");
        scanf("%f", &array[i].celcius);
        
        array[i].fahrenheit=array[i].celcius*1.8+32;
        sum+=array[i].celcius;
    }
    
    average1=sum/5;
    average2=avarage1*1.8+32;
    
    for(i=0;i<5;i++)
    {        
        printf("%s -> %.1f celsius degrees -> %.1f fahrenheit degrees \n", array[i].city, array[i].celcius, array[i].fahrenheit);
    }
    printf("The average temperature is %.1f celcius degrees -> %.1f fahrenheit degrees", average1, average2);
    return 0;
}