CODEWITHSUNDEEP
cfileloopsfor-loopwhile-loop
serkanhelvacioglu
serkanhelvacioglu

Reputation: 63

How can I use feof with while loop?

I want to get student name mid-term and final points and write them in a txt file but when I use a loop, It never get student name. It always gives it a miss. How can I use feof with a loop? I want to get student names mid-term and final point and calculate the average from the got points and It must get always name and points till user press the end of file.

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
#include<conio.h>

void main()
{
FILE *Points;

char namesOfStudents[10];
int pointsOfStudents[1][2];
double AverageOfStudents[1];
int i=0,j=1;
int numberOfStudents;

Points = fopen("C:\\Users\\Toshiba\\Desktop\\PointsOfStudent.txt", "a+");
fprintf(Points, "Name\t\t 1.Grade\t2.Grade\t\tAverage\n");
/*  printf("How many students will you enter: ");
scanf("%d",&numberOfStudents);*/

//while (!feof(Points))

printf("Please enter new students name: ");
gets(namesOfStudents);
printf("\nPlease enter new students first point: ");
scanf("%d",&pointsOfStudents[0][0]);
printf("\nPlease enter new students second point: ");
scanf("%d",&pointsOfStudents[0][1]);


        for (; i < strlen(namesOfStudents); i++)
            {
                fprintf(Points, "%c", namesOfStudents[i]); //To write 
     student name to file

            }
        fprintf(Points,"\t\t   ");

        fprintf(Points,"%d\t\t",pointsOfStudents[0][0]);  //to write 
student's first point
        fprintf(Points,"%d\t\t",pointsOfStudents[0][1]);  //to write 
student's second point  

        fprintf(Points,"%d\n",(pointsOfStudents[0][0]+pointsOfStudents[0]
[1])/2);    //to calculate and write average 
        system("cls");

        fclose(Points);

system("Pause");
}

Upvotes: 1

Views: 1548

Answers (1)

John Bode
John Bode

Reputation: 123596

Several things:

First, NEVER NEVER NEVER NEVER NEVER use gets - it is dangerous, it will introduce a point of failure and/or massive security hole in your code, and it has been removed from the standard library as of the 2011 version of the language standard. Use fgets instead:

fgets( nameOfStudents, sizeof nameOfStudents, stdin );

Secondly, while( !feof( fp ) ) is always wrong. On input from fp, it will loop one time too often. On output to fp, it is meaningless.

You can use the result of fgets to control your loop:

while ( fgets( nameOfStudents, sizeof nameOfStudents, stdin ) )
{
  ...
}

When you're done entering data from the terminal, signal an EOF using either CtrlZ or CtrlD (depends on your platform).

Third, main returns int, not void; use

int main( void )

instead.

Finally, change

for (; i < strlen(namesOfStudents); i++)
{
  fprintf(Points, "%c", namesOfStudents[i]); //To write student name to file
}

to

fprintf( Points, "%s", nameOfStudents );

to write the student name to the file.

There are other problems, but make those changes and see if that doesn't help.

Upvotes: 3

Related Questions