Simple Program not working right (in C)

I just made this C program in Codewarrior for mac using the "PPC console C App:"

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

int main()
{

float fuel_flow;
float total_fuel;
float TAS;

char TAS1[6];
char total_fuel1[16];
char fuel_flow1[12];
char yn='y';

while(yn=='y')
{

printf("What is your fuel flow in pounds? ");
gets(fuel_flow1);
fuel_flow=atoi(fuel_flow1);

printf("What is your total fuel availible in pounds? ");
gets(total_fuel1);
total_fuel=atoi(total_fuel1);

printf("What is your true airspeed in knots? ");
gets(TAS1);
TAS=atoi(TAS1);

printf("\nEndurance: %.2f hrs\n",total_fuel/fuel_flow);
printf("Range: %.1f nm\n",total_fuel/fuel_flow*TAS);
printf("\nCalculate again? y/n ");
yn=getchar();

}
printf("Done!");
return 0;

}

Here is my problem. The first run of the program is good. After the program asks "Calculate Again?" , i type in "y" and then on the next line it prints the first two printfs; printf("What is your fuel flow in pounds? "); and printf("What is your total fuel availible in pounds? "); on the same line and everything gets messed up after that until i re run the program. Could there be something wrong in my while loop? It would be great if anyone can help. thank you.

Hey man..
no problem..I think I fixed the problem..you had to FLUSH at the end of the loop..the revised code is here now!
Btw..you had a typo.."availible" should be spelt "available"..I fixed that too..
If you want a better understanding of FLUSH reply back and I'll post a previous msg..Okee..
A :)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#define FLUSH while(getchar() != '\n')

int main()
{

float fuel_flow;
float total_fuel;
float TAS;

char TAS1[6];
char total_fuel1[16];
char fuel_flow1[12];
char yn='y';

while(yn=='y')
{

printf("What is your fuel flow in pounds? ");
gets(fuel_flow1);
fuel_flow=(float) atoi(fuel_flow1);

printf("What is your total fuel available in pounds? ");
gets(total_fuel1);
total_fuel=(float) atoi(total_fuel1);

printf("What is your true airspeed in knots? ");
gets(TAS1);
TAS= (float) atoi(TAS1);

printf("\nEndurance: %.2f hrs\n",total_fuel/fuel_flow);
printf("Range: %.1f nm\n",total_fuel/fuel_flow*TAS);
printf("\nCalculate again? y/n ");
yn=getchar();

FLUSH;

}
printf("Done!");
return 0;

}

---

FLUSH ur buffer stream :)

Your program's problem is similar to so many programs posted in
the past. Do a search if ya like.

Here is my fix to the problem:
int main()
{

float fuel_flow;
float total_fuel;
float TAS;

char TAS1[6];
char total_fuel1[16];
char fuel_flow1[12];
char yn; /* declare a variable */

do
{

printf("What is your fuel flow in pounds? ");
gets(fuel_flow1);
fuel_flow=atoi(fuel_flow1);

printf("What is your total fuel availible in pounds? ");
gets(total_fuel1);
total_fuel=atoi(total_fuel1);

printf("What is your true airspeed in knots? ");
gets(TAS1);
TAS=atoi(TAS1);

printf("\nEndurance: %.2f hrs\n",total_fuel/fuel_flow);
printf("Range: %.1f nm\n",total_fuel/fuel_flow*TAS);
printf("\nCalculate again? y/n ");
yn=getch(); /*if you use getchar(), you need to use fflush() */

} while (yn == 'y' || yn == 'Y')
printf("Done!");
return 0;

}
Let me know if it does'nt work.
DV007

WOW! You guys are the greatest! I didn't expect help this quick. Any way it works yes! I really didn't know I had to use the flush stuff. I am new to progamming in C, of course.. I am using my C for dummies book :-). To dv007: I dont think that the getch(); will work on a Mac with codewarrior. To aspand: yes I would like to know what the flush is used for! Thanks.

Hey DruzTito,
This is the link to a msg I posted asking help about FLUSH..pay close attention to Prelude and esp. Hammer's comments..should be helpful! I am glad the program worked just fine for you now
Aspan :D