How to make compiler repeat until the number 0 is presed - c

Question

I'm wondering how to make the compiler repeat itself if the user presses a random button at the end. But if the user presses "0" the compiler exits.
My code:
#include<stdio.h>
#include<stdlib.h>
#include <math.h>
#include <float.h>
struct mystruct
{
float startnummer;
float hoppnummer;
float svarighetsgrad;
float domarpoangs[7];
};
int main(void)
{
struct mystruct data;
float max = 0;
float min = FLT_MAX;
float sum = 0;
float avg = 0;
int i = 0;
float resultat = 0;
printf("Startnummer: \n");
scanf_s("%f", &data.startnummer);
printf("Hoppnummer:\n");
scanf_s("%f", &data.hoppnummer);
printf("Svarighetsgrad:\n");
scanf_s("%f", &data.svarighetsgrad);
for (i = 0; i < 7; i++)
{
printf("domarpoang %d\n", i + 1);
float f;
if (scanf_s("%f", &f) == 1)
{
if (f < min) min = f;
if (f > max) max = f;
data.domarpoangs[i] = f;
}
else
{
printf("error parsing float\n");
exit(0);
}
}
system("cls");
printf("Startnummer: %.1f \n", data.startnummer);
printf("Hoppnummer: %.1f\n", data.hoppnummer);
printf("Svarighetsgrad: %.1f\n", data.svarighetsgrad);
for (i = 0; i < 7; i++)
{
printf("Domarpoang %d: %.1f\n", (i + 1), data.domarpoangs[i]);
}
for (i = 0; i < 7; i++)
{
sum += data.domarpoangs[i];
}
sum = sum - (max + min);
avg = sum/5;
resultat = avg * 3 * data.svarighetsgrad;
printf("Hoppoang:%.2f \n", resultat);
printf("Tryck tangent for nytt hopp!");
getchar();
getchar();
return 0;
}
*If the user presses random button, the compiler repeat itself from the beginning
*If the user presses 0, the compiler exits.
Any help is appreciated, thank you.

Answer 1

This answer puts a loop around the body of your main() code, taking care to re-initialise some of the variables for the next iteration.
There are many SO questions about getting keyboard input and clearing the debris. I know of no simple standard ways of testing for keyboard input such as kbhit(), for taking a single key input such as getch() or for flushing the input. Even getchar() is horrible - it won't return until you have pressed "Enter" which it leaves in the input buffer. This has resulted in many SO answers with impenetrable (to me) formats for scanf() to flush the input, or testing if (getchar() == EOF) - which does not respond to the "Enter" key.
So I have put a simple wrapper around the main() code, which terminates when '0' is entered followed by a control char (because fgets() appends the newline) or terminator. This removes the need to clean up the input - except in the case where the user inputs some silly typing. GIGO!
#include <stdio.h>
#include <float.h>
#define BUFFSIZE 10
struct mystruct {
float startnummer;
float hoppnummer;
float svarighetsgrad;
float domarpoangs[7];
};
int main(void)
{
char kbuff [BUFFSIZE+1];
struct mystruct data;
float max;
float min;
float sum;
float avg;
int i;
float resultat;
do {
max = 0; // initialise for each loop
min = FLT_MAX;
sum = 0;
printf ("Body of your main loop\n");
fgets(kbuff, BUFFSIZE, stdin);
} while (kbuff[0] != '0' || kbuff[1] >= ' ');
return 0;
}