I need help adding on to my C program. it can't be C+, has to be regular C. This is what I have so far:

#include

main ()

{

int num_years; float ror, interest_earned, total, investment; double arr[10];

while(1)

{

printf("Enter the initial investment: $");

scanf("%lf", &arr[0]);

if(arr[0] > 0 && arr[0] <= 5000) break;

else printf("Amount not in rangen");

}

printf("n Please enter the number of years left to retire n");

fflush(stdin);

scanf("%d",&num_years);

if(num_years<1||num_years>50)

{

printf("Enter value between 1 and 50");

scanf("%d",&num_years);

}

printf("n Please enter the assumed rate of return on the investment n");

scanf("%f",&ror);

if(ror<-15 or ror>15)

{

printf("Enter value between -15 and 15");

scanf("%f",&ror); }

printf("Enter the initial investment: $");

scanf("%f", &investment);

interest_earned=(float)(investment*ror*num_years)/100;

printf("The interest on your investment %f is %f n",investment, interest_earned);

total=investment+interest_earned;

printf("You will recieve the amount %f at the time of retirement n",total);

}

What would I write to prevent any calculations if any of the previous three values are invalid and then once a valid value has been entered into element zero of the float array, copy the starting value into element zero of the second array. (second float array must be created)