I am a newcomer to programming. My English is bad so I used google translate to ask this question:
I'm practicing using input/output in C language. I wrote a C program that takes a file called sample.txt and writes a few lines of words in it. I feel that the program that I made is correct but I found an error when compiling the program.
#include <stdio.h>
int main(){
FILE *fptr;
int n,I;
char text[100];
fptr=fopen("sample.txt","w");
printf("Number of line? ");
scanf("%d",&n);
printf("\n");
for( i = 1; i <= n; i++){
printf("Line %d: ", I);
fgets(text, sizeof(text), stdin);
fputs(text, fptr);
}
fclose(fptr);
return 0;
}
This is the output : enter image description here. enter image description here
Why line 1 and 2 are not separate like the others? I've checked several times and I don't know what went wrong.
As already pointed out by people in comments, you need to handle the newline left by scanf so that it doesn't get consumed by fgets() afterwards. You can either add a getchar() after scanf to handle this:
printf("Number of line? ");
scanf("%d",&n);
getchar();
Or you can replace usage of scanf for taking input with fgets() followed by a sscanf:
char input[10];
...
fgets(input, 10, stdin);
sscanf(input, "%d", &n);
When I made this changes, I was able to see desired output:
c-posts : $ ./a.out
Number of line? 3
Line 1: Foo
Line 2: Bar
Line 3: Pong
c-posts : $ cat sample.txt
Foo
Bar
Pong