C Exercises: Append multiple lines at the end of a text file

Last update on March 20 2025 12:32:29 (UTC/GMT +8 hours)

10. Append Multiple Lines to File

Write a program in C to append multiple lines to the end of a text file.

Assume that the content of the file test.txt is :                                                                       
test line 1                                                                                                   
test line 2                                                                                                   
test line 3                                                                                                   
test line 4

Sample Solution:

C Code:

#include <stdio.h>

int main ()
{
  FILE * fptr;
  int i,n;
  char str[100];
  char fname[20];
  char str1;
  
	printf("\n\n Append multiple lines at the end of a text file :\n");
	printf("------------------------------------------------------\n"); 
	printf(" Input the file name to be opened : ");
	scanf("%s",fname);		
    fptr = fopen(fname, "a"); 
    printf(" Input the number of lines to be written : ");
    scanf("%d", &n);
    printf(" The lines are : \n");  
    for(i = 0; i < n+1;i++)
    {
    fgets(str, sizeof str, stdin);
    fputs(str, fptr);
  }
  fclose (fptr);
//----- Read the file after appended ------- 
	fptr = fopen (fname, "r");  
	printf("\n The content of the file %s is  :\n",fname);
	str1 = fgetc(fptr);
	while (str1 != EOF)
		{
			printf ("%c", str1);
			str1 = fgetc(fptr);
		}
    printf("\n\n");
    fclose (fptr);
//------- End of reading ------------------
  return 0;
}

Sample Output:

 Append multiple lines at the end of a text file :                                                            
------------------------------------------------------                                                        
 Input the file name to be opened : test.txt                                                                  
 Input the number of lines to be written : 3                                                                  
 The lines are :                                                                                              
test line 5                                                                                                   
test line 6                                                                                                   
test line 7                                                                                                   
                                                                                                              
 The content of the file test.txt is  :                                                                       
                                                                                                              
test line 1                                                                                                   
test line 2                                                                                                   
test line 3                                                                                                   
test line 4                                                                                                   
                                                                                                              
test line 5                                                                                                   
test line 6                                                                                                   
test line 7

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to append a block of text with a header and footer to the end of an existing file.
Write a C program to append user-input lines to a file and then display only the newly added lines.
Write a C program to append lines to a file only if they do not already exist in the file.
Write a C program to append multiple lines to a file and timestamp each appended line.

C Programming Code Editor:

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