string - How do I write to a specific line of file in c? -

so have project doing , have created program allows user write file, shown below:

 #include <stdio.h>  #include <stdlib.h>   file *fd;  file *fw;       struct store      {           char word[512];           char nword[512];      }      stock;       struct store2      {           char definition[512];      }      stock2;  char done='y'; int count=1; int c=0; int d=0;  int main(void) {     fw=fopen("test z w.txt","w");     fd=fopen("test z d.txt","w");          {              printf("word %d: ",count);          gets(stock.word);          while((c= getchar()) != '\n' && c != eof);           printf("definition %d: ",count);          gets(stock2.definition);          while((c= getchar()) != '\n' && c != eof);             fprintf(fw,"%s\n", stock.word);                   fprintf(fd,"%s\n", stock2.definition);                  count=count+1;            system("cls");                     }     while (count<11);  fclose(fd); fclose(fw);  return 0;  } 

this code fine, however, expand there option edit 1 chosen line, rather wiping entire file , writing of contents again.

all have work on using how write specific line of txt file in c?

which wasn't helpful since couldn't take answer , import code, either way need error such 1 below, can fixed easily.

 1  2  3  4  5  6  7  8  9  10 

where user automatically asked line want edit.

#include <stdio.h> int main() {     file *fp,*fc;     int linenum;  //stores line number should edited.     int count=0;  //count number lines in source file.     int ch;   //temporary place store character of source file(one @ time).     int edited=0;  //0=false , 1=true     int t;   //temporary place store input want replaced error in text file.       fp=fopen("source.txt","r");     fc=fopen("target.txt","w");      if(fp==null||fc==null)     {         printf("\nerror...cannot open/create files");         return 1;     }      printf("\nenter line number want 2 edit: ");     scanf("%d",&linenum);      while((ch=fgetc(fp))!=eof)     {         if(ch=='\n')  //counts number of lines             count++;         if(count==linenum-1 && edited==0)  //if specific line(error line) found , line still not edited. more explanation:- if want edit 3rd line should start writing @ end of 2nd line(hence count==linenum-1) , edited==0 means error line still not edited.          {             printf("\nenter input store @ line %d:",linenum);              scanf(" %c",&t);  //you can replace statement input operation want replace error line.              if(count==0)  //if first line edit..                 fprintf(fc,"%s\n",t)   //watch closely,no '\n' before %s,this copy without creating newline in beginning of new file.             else                  fprintf(fc,"\n%s\n",t);  //stores input @ error line in file fc(target.txt) variable t.              edited=1;  //this prevents loop execute more once(as error edited),so there no need execute loop till end of program              while( (ch=fgetc(fp))!=eof )  //actually loop skips existing line in source.txt(see below)             {                           //we want skip line because error line.                 if(ch=='\n')//this break when next new line(after error line skipped) found.                     break;             }        }        else           fprintf(fc,"%c",ch);     }     fclose(fp);     fclose(fc);      if(edited==1)         printf("\ncongrates...error edited successfully.");     else         printf("\nline not found");  return 0; } 

this program open source file (which may have error,i called source.txt*) , keeps reading character character , write new file (target.txt) untill (eof) found.but stop @ specific line , ask user input data written in place of error(error line source file) in new text file( target.txt).

so @ end target.txt file free errors. open , check it.

in program have assumed want replace single character @ line 3.but can change operation replace string,float or integers etc.

here output:-

enter line number want 2 edit: 3

enter input store @ line 3: 3

congrates...errors edited successfully.

contents of target.txt:-

1

2

3

4

5

6

7