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Floating point exception on C, can't solve


I wrote a very simple code and when I compiled (Which I told it that when I enter END whatever case it should break that program.) but there is message show up "Floating point exception: 8", I never saw this message before and I have been searching Google which told me that I have something going on with float value that allow program to do something that it shouldn't.

/* Program: Taxi Day    
 *
 * Description: Calculate fartest taxi distance.
 *
 * Creator: Thunpisit Amnuaikiatloet #57070503418
 *
 * Create on: November. 26, 2014   17.55.00
 *
 * Lastest modify on: November. 26, 2014   17.55.00
 */

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

int main()
{
char buffer[128];
char END[8] = ("END");
char MAXNAME[128];
int MAXRANGE = 0;
char taxiNumber[32];
int taxiStart = 0;
int taxiEnd = 0;
int taxiTotal = 0;
int taxiCount = 0;

while(1)
{
    /* Ask user to enter Taxi Number */
    printf("\nENTER TAXI NUMBER: ");
    fgets(buffer,sizeof(buffer),stdin);
    sscanf(buffer,"%s",taxiNumber);

    /* If Taxi Number entered is END, stop asking */
    if(strcasecmp(taxiNumber,END) == 0)
    {
        break;
    }

    /* Check Taxi Number validate */
    while(strlen(taxiNumber) > 10)
    {
        printf("ENTER TAXI NUMBER: ");
        fgets(buffer,sizeof(buffer),stdin);
        sscanf(buffer,"%s",taxiNumber);
    }

    /* Ask user to enter start km */
    printf("ENTER START KM?: ");
    fgets(buffer,sizeof(buffer),stdin);
    sscanf(buffer,"%d",&taxiStart);

    /* Check Taxi Start validate */
    while(taxiStart < 0)
    {
        printf("ENTER START KM?: ");
        fgets(buffer,sizeof(buffer),stdin);
        sscanf(buffer,"%d",&taxiStart);
    }

    /* Ask user to enter end km */
    printf("ENTER END KM?: ");
    fgets(buffer,sizeof(buffer),stdin);
    sscanf(buffer,"%d",&taxiEnd);

    /* Check Taxi Start validate */
    while(taxiStart > taxiEnd)
    {
        printf("ENTER END KM?: ");
        fgets(buffer,sizeof(buffer),stdin);
        sscanf(buffer,"%d",&taxiEnd);
    }

    /* Calculate total distance for each taxi */
    taxiTotal = taxiEnd - taxiStart;
    printf("----------------------------------");

    /* Show taxi entered information */
    printf("\nTAXI %s HAS TRAVELED %d KM\n",taxiNumber,taxiTotal);

    /* Compute the taxi that have largest distance */
    if(MAXRANGE < taxiTotal)
    {
        MAXRANGE = taxiTotal;
        strcpy(MAXNAME,taxiNumber);
    }

    /* Count number of taxi entered */
    taxiCount++;
}

/* Print Summary */
printf("\nTAXI %s DROVE THE LONGEST RANGE, WHICH IS %d KM",MAXNAME,MAXRANGE);
printf("THERE ARE %d TAXIS TODAY, AVERAGE RANGE ARE %d KM",taxiCount,taxiTotal/taxiCount);
}

Solution

  • This likely happens because taxiTotal/taxiCount performs a division by zero - which results in an error (manifested as a floating point exception, even if you're just using integers).

    That means taxiCount is 0, so you should probably rather do

    if (taxiCount > 0) {
        printf("THERE ARE %d TAXIS TODAY, AVERAGE RANGE ARE %d KM",taxiCount,taxiTotal/taxiCount);
    } else {
        puts("THERE ARE NO TAXIS TODAY");
    }