CODEWITHSUNDEEP
cfile-ioeofstdio
prateekj_ahead
prateekj_ahead

Reputation: 157

Why does the first run of this simple file-read program takes 30 secs to execute?

When I run the program for the first time, the file gets created. But it seems the while loop takes a long time to get over. Doesnt it get an EOF in the beginning of the file since the file is empty as of now?

#include<stdio.h>
void main(){
    FILE *p;
    int b, a=0;b=0;
    p=fopen("text.txt", "a+");
    while((b=fscanf(p,"%d",&a)) != EOF)
        printf("%d\n",a);
    fseek(p, 0, SEEK_END);
    fprintf(p, " %d %d",1,6);
    fflush(p);
    fclose(p);
}

Upvotes: 0

Views: 108

Answers (1)

perreal
perreal

Reputation: 97958

Make sure fscanf returns 1:

#include<stdio.h>
int main(){
    FILE *p;
    int b=0, a=0;
    p=fopen("text.txt", "a+");
    while((b=fscanf(p,"%d",&a)) == 1)
        printf("%d\n",a);
    // no need to seek, or flush
    fprintf(p, " %d %d",1,6);
    fclose(p);
    return 0;
}

Upvotes: 1

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