File does not fprint correctly in C? - c

Question

So here I have a basic program that will write to a specific line in a file by writing the contents of the file into a temporary file where the new line is written and then the contents of that file is then copied back into the starting file.
(Scores) = File
(Sub) = Temp
#include <stdio.h>
#include <conio.h>
#include <string.h>
void insert(void);
int main()
{
insert();
}
void insert(void)
{
FILE *fp,*fc;
int lineNum;
int count=0;
char ch=0;
int edited=0;
int score=0;
fp=fopen("Test 02 Scores.txt","r");
fc=fopen("Sub.txt","w");
if(fp==NULL||fc==NULL)
{
printf("\nError...cannot open/create files");
exit(1);
}
printf("Enter the score");
scanf("%d",&score);
printf("\nEnter Line Number Which You Want 2 edit: ");
scanf("%d",&lineNum);
while((ch=fgetc(fp))!=EOF)
{
if(ch=='\n')
count++;
if(count==lineNum-1 && edited==0)
{
if(lineNum==1)
{
fprintf(fc,"%d\n",score);
}
else
fprintf(fc,"\n%d\n",score);
edited=1;
while( (ch=fgetc(fp))!=EOF )
{
if(ch=='\n')
break;
}
}
else
fprintf(fc,"%d",ch);
}
fclose(fp);
fclose(fc);
if(edited==1)
{
printf("\nLine has been written successfully.");
char ch;
FILE *fs, *ft;
fs = fopen("Sub.txt", "r");
if( fs == NULL )
{
printf("File is not real");
exit(1);
}
ft = fopen("Test 02 Scores.txt", "w");
if( ft == NULL )
{
fclose(fs);
printf("File is not real\n");
exit(1);
}
while( ( ch = fgetc(fs) ) != EOF )
fputc(ch,ft);
printf("\nFile copied\n");
getch();
fclose(fs);
fclose(ft);
}
else
printf("\nLine Not Found");
}
However, a problem has arisen, I started to write this code for use with strings, but since decided to use number values, whenever I try to copy with the integer values the program will not copy anything right, I Know this may be caused by the char to int but I'd rather have more help in assessing where I should change stuff.

Answer 1

The error is in this line
fprintf(fc,"%d",ch)
%d prints ch as an integer, not as a character, you should instead write
fprintf(fc,"%c",ch)
or use fputc()
There are some small issues with your code, here is a working version. I added comments where I changed things.
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h> // needed for exit()
void insert(void);
int main()
{
insert();
}
// use fgets to read from keyboard, it is simpler.
int readNumber()
{
char buffer[64] = {0};
fgets(buffer, sizeof(buffer), stdin);
return atoi(buffer);
}
void insert(void)
{
FILE *fp = NULL; // prefer one decl per row
FILE *fc = NULL;
int lineNum = 0;
int count=0;
int ch=0; // should be int ch=0;
int edited=0;
int score=0;
// file names
const char src[] = "Test 02 Scores.txt";
const char dest[] = "Sub.txt";
fp=fopen(src,"r");
if(fp==NULL)
{
perror(src); // use perror() instead for better error msg
exit(EXIT_FAILURE); // there are std constants for exit args
}
fc=fopen(dest,"w");
if(fc==NULL)
{
perror(dest);
exit(EXIT_FAILURE);
}
printf("Enter the score: ");
score = readNumber(); // using fgets to avoid lingering \n in buffer
printf("\nEnter Line Number Which You Want 2 edit: ");
lineNum = readNumber();
while((ch=fgetc(fp))!=EOF) // fgetc returns int so ch should be int
{
if(ch=='\n') // better to have {} here too
{
count++;
}
if(count==lineNum-1 && edited==0)
{
if(lineNum==1)
{
fprintf(fc,"%d\n",score);
}
else // better to { } here too
{
fprintf(fc,"\n%d\n",score);
}
edited=1;
// i guess you want to remove old score
while( (ch=fgetc(fp))!=EOF )
{
if(ch=='\n')
{
break;
}
}
}
else // {} for avoiding future pitfall
{
fputc(ch,fc);
}
}
fclose(fp);
fclose(fc);
if(edited==1)
{
puts("\nLine has been written successfully."); // puts() when u can
int ch = 0; // int
FILE *fs = NULL;
FILE *ft = NULL;
fs = fopen(dest, "r");
if( fs == NULL )
{
perror(dest);
exit(EXIT_FAILURE);
}
ft = fopen(src, "w");
if( ft == NULL )
{
perror(src);
exit(EXIT_FAILURE); // at program exit files will close anyway
}
while( ( ch = fgetc(fs) ) != EOF )
{
fputc(ch,ft);
}
fclose(fs);
fclose(ft);
printf("\nFile copied\n");
getch();
}
else
{
printf("\nLine Not Found");
}
}