Example : Write a program (WAP) in C to create new blank file with a name in C.
#include<stdio.h>
#include<conio.h>
void main()
{
FILE *fp;
char Str[30];
printf("Enter the file name we want to create : ");
scanf("%s",Str);
fp=fopen(Str,"w");
if(fp==NULL)
{
printf("File Not Created");
exit(0);
}
printf("File is created successfully.");
getch();
}
Output:
Enter the file name we want to create : abc
File created successfully.
(NB : New file 'abc' of unknown type is created in the same directory where program is saved.)
Enter the file name we want to create : abc.txt
File created successfully.
(NB : New Notepad file 'abc.txt' is created in the same directory where program is saved.)
Enter the file name we want to create : abc.docx
File created successfully.
(NB : New Word file 'abc.docx' is created in the same directory where program is saved.)
Enter the file name you want to create : F:\abc.txt
File created successfully.
(NB : New file 'abc.txt' is created in the F drive of the system.)
Example : WAP in C to check whether a file is present/created or not.
#include<stdio.h>
#include<conio.h>
void main()
{
FILE *fp; /* File Pointer declaration(fp) to store the address of first character of file
contents */
char c;
fp= fopen ("F:\\New folder\\abc.txt", "r"); // To Open an existing file in Read mode(r)
fp= fopen ("F:\\New folder\\abc.txt", "w"); // To Open an existing file in Write mode(w)
if (fp==NULL)
{
puts("File does not exists");
exit(0);
}
else
{
puts("File Exists");
}
fclose(fp); // To close the file
getch();
}
NB : 'Read mode' is used to display the contents whereas 'Write mode' is for Store/save the contents in the file.
Example : WAP in C to store certain string messages into a file.
#include<stdio.h>
#incluce<conio.h>
int main()
{
FILE *fp;
fp = fopen("F:\\New folder\\abc.txt","w");
fprintf(fp, "%s", "This is a codershelpline site for all");
fclose(fp);
return 0;
}
NB : Here the string messages 'This is a codershelpline site for all' is stroed in "F:\\New
folder\\abc.txt" the file.
Example : WAP in C to create new file, write/store data into it and display them.
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
FILE *fp;
char filename[30];
printf("\nEnter File Name You Want to Create : ");
scanf("%s",filename);
fp=fopen(filename,"w");
if(fp==NULL)
{
printf("File Does Not Created");
exit(0);
}
printf("New File created successfully.");
putc('C',fp); //writting single character into file
putc('H',fp);
putc('L',fp);
printf("\nData is stored/written in file successfully.\n");
fclose(fp);
fp=fopen(filename,"r");
printf("Contents of file is/are :\n");
printf("%c",getc(fp));
printf("%c",getc(fp));
printf("%c",getc(fp));
fclose(fp);
getch();
}
Output :
Enter File Name You Want to Create : abc.txt
New File created successfully.
Data is stored/written in file successfully.
Contents of file is :
CHL
/* -------------- OR -----------------*/
#include <stdio.h>
#include <conio.h>
#include <string.h>
void main( )
{
FILE *fp ;
char str[150];
fp = fopen("abc.c", "w") ; //Creates a new file & opens in write mode.
printf("Enter the characters for new file below 150 size\n");
while (strlen(gets(str))>0)
{
fputs(str, fp) ;
fputs("\n", fp) ;
}
fclose(fp) ;
fp = fopen("abc.c", "r") ;
printf( "The outputs are" ) ;
while( fgets ( str, 150, fp ) != NULL )
printf( "%s" , str ) ;
fclose(fp) ;
getch();
}
NB : Enter data line by line by pressing enter key but to come out from it, wait few seconds and then
press enter button.
Example : WAP in C to store student records in a file and display them.
#include<stdio.h>
#include<conio.h>
void main()
{
FILE *fp;
char sname[80] ,ch;
int sage;
float fee;
fp = fopen("student.txt", "w");
if (fp == NULL)
{
printf("File does not exist.\n");
return;
}
printf("Enter student name: \n");
scanf("%s", sname);
fprintf(fp, "student name = %s\n", sname);
printf("Enter student age: \n");
scanf("%d", &sage);
fprintf(fp, "student age is = %d\n", sage);
printf("Enter student course fee:\n");
scanf("%f", &fee);
fprintf(fp, "student fee is = %.2f\n", fee);
fclose(fp);
printf("\nThe output is : \n\n");
fp=fopen("student.txt","r");
while((ch=getc(fp))!=EOF)
{
printf("%c",ch);
}
fclose(fp) ;
getch();
}
Output :
Enter student name:
Sohan
Enter student age:
35
Enter student course fee:
501.75
The output is :
student name = Sohan
student age is = 35
student fee is = 501.75
Example : A simple file handling program in C to display the output of file contents.
#include <stdio.h>
#include<conio.h>
void main()
{
FILE *fp; /* File Pointer declaration(fp) to store the address of first character of file
contents */
char ch;
fp= fopen ("G:\\New folder\\abc.txt", "r"); // To Open an existing file in Read mode(r)
if (fp==NULL)
{
puts("Unable to Open Existing File");
exit(0);
}
else
{
while(1)
{
ch = fgetc(fp); // To read/extract file contents character by character.
if(ch==EOF) // To check the contents of file till the end
break;
else
printf("%c", ch);
}
}
fclose(fp); // To close the file
getch();
}
/* ---------- OR ------------ */
#include<stdio.h>
#include<conio.h>
void main()
{
FILE *fp = fopen("F:\\New folder\\abc.txt", "r");
int ch = getc(fp);
while (ch != EOF)
{
putchar(ch);
ch = getc(fp);
}
if (feof(fp))
printf("\n Now the contents reached the end of file.");
else
printf("\n File contents traverse improperly");
fclose(fp);
getchar();
}
Output :
(NB : First of all 'abc.txt' file message is displayed and then EOF message.)
This is a codershelpline site for all
Now the contents reached the end of file.
Example : A file handling program in C to count the number of lines present in a file.
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include<stdlib.h>
void main( )
{
FILE *fp ;
char str[150],ch;
int count=0;
fp = fopen("abc.c", "w") ; //Create a new file & open in write mode.
printf("Enter the characters for new file below size 150\n");
while (strlen(gets(str))>0)
{
fputs(str, fp) ;
fputs("\n", fp) ; // insert new line after pressing enter key during input and pressing twice enter key without typing anything to come out from input.
}
fclose(fp) ;
fp = fopen("abc.c", "r") ;
if(fp==NULL)
{
printf("File does not exist!!!\n");
exit(0);
}
//read character by character to check new line
while((ch=fgetc(fp))!=EOF)
{
if(ch=='\n')
count++;
}
fclose(fp);
printf("Total number of lines are : %d\n",count);
getch();
}
Example : WAP in C to create new file, store data in it and rename the created file.
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include<ctype.h>
void main( )
{
FILE *fp ;
char str[150],ch;
int count=0;
fp = fopen("abc.c", "w") ; //Create a new file & open in write mode.
printf("Enter the characters for new file below size 150\n");
while (strlen(gets(str))>0)
{
fputs(str, fp) ;
fputs("\n", fp) ;
}
fclose(fp) ;
rename("abc.c","simple.c");
getch();
}
Example : WAP in C to remove/delete a created/existing file.
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include<ctype.h>
void main( )
{
FILE *fp ;
char str[150],ch;
int count=0;
fp = fopen("abc.c", "w") ; //Create a new file & open in write mode.
printf("Enter the characters for new file below size 150\n");
while (strlen(gets(str))>0)
{
fputs(str, fp) ;
fputs("\n", fp) ;
}
fclose(fp) ;
remove("abc.c");
printf("Created/Existing File is Deleted\n");
fp=fopen("abc.c","r");
if(fp==NULL)
{
printf("File is not Present\n");
}
getch();
}
Example : WAP in C to count the number of characters present in a created/existing file.
#include<stdio.h>
#include<conio.h>
void main()
{
FILE *fp;
char sname[80], ch;
int sage,count=0;
float fee;
fp = fopen("student.txt", "w");
if (fp == NULL)
{
printf("File does not exist.\n");
return;
}
printf("Enter student name: \n");
scanf("%s", sname);
fprintf(fp, "student name = %s\n", sname);
printf("Enter student age: \n");
scanf("%d", &sage);
fprintf(fp, "student age is = %d\n", sage);
printf("Enter student course fee:\n");
scanf("%f", &fee);
fprintf(fp, "student fee is = %.4f\n", fee);
fclose(fp);
printf("\nThe output of file is : \n\n");
fp=fopen("student.txt","r");
while((ch=getc(fp))!=EOF)
{
printf("%c",ch);
count++;
}
fclose(fp) ;
printf("\nTotal number of characters in the file is = %d\n",count);
getch();
}
Example : How to copy the contents of one file into another file and display them.
#include <stdio.h>
#include <conio.h>
#include <string.h>
void main( )
{
FILE *fp,*fp1 ;
char str[150],ch;
fp = fopen("abc.c", "w") ; //Create a new file & open in write mode.
printf("Enter the characters for new file below 150\n");
while (strlen(gets(str))>0)
{
fputs(str, fp) ;
fputs("\n", fp) ;
}
fclose(fp) ;
fp1=fopen("simple.c","w");
fp = fopen("abc.c", "r") ;
while((ch=fgetc(fp))!=EOF)
{
putc(ch,fp1);
}
fclose(fp) ;
fclose(fp1) ;
fp1=fopen("simple.c","r");
printf( "The copied values are :\n" ) ;
while((ch=getc(fp1))!=EOF)
{
printf("%c",ch);
}
fclose(fp1) ;
getch();
}
Example : How to convert lowercase letters of one file into uppercase letters in another file and display them.
#include <stdio.h>
#include <conio.h>
#include <string.h>
void main( )
{
FILE *fp,*fp1 ;
char str[150],ch;
fp = fopen("abc.c", "w") ; //Create a new file & open in write mode.
printf("Enter the characters for new file below 150\n");
while (strlen(gets(str))>0)
{
fputs(str, fp) ;
fputs("\n", fp) ;
}
fclose(fp) ;
fp1=fopen("simple.c","w");
fp = fopen("abc.c", "r") ;
while((ch=fgetc(fp))!=EOF)
{
if(islower(ch))
{
ch=ch-32;
}
putc(ch,fp1);
}
fclose(fp) ;
fclose(fp1) ;
fp1=fopen("simple.c","r");
printf( "The outputs are \n" ) ;
while((ch=getc(fp1))!=EOF)
{
printf("%c",ch);
}
fclose(fp1) ;
getch();
}
Example : How to merge two file contents into one file and display them.
#include <stdio.h>
#include <conio.h>
#include <string.h>
void main( )
{
FILE *fp1,*fp2,*fp3 ;
char str1[150],str2[150],str3[300],ch;
fp1 = fopen("abc.c", "w") ; //Create a new file & open in write mode.
printf("Enter the characters in first file below 150 size\n");
while (strlen(gets(str1))>0)
{
fputs(str1, fp1) ;
fputs("\n", fp1) ; //sends cursor in new line after insertion of characters.
}
fclose(fp1) ;
fp2 = fopen("simple.c", "w") ; //Create a new file & open in write mode.
printf("Enter the characters in second file below 150 size\n");
while (strlen(gets(str2))>0)
{
fputs(str2, fp2) ;
fputs("\n", fp2) ;
}
fclose(fp2) ;
fp3=fopen("xyz.c","w");
fp1=fopen("abc.c","r");
while((ch=fgetc(fp1))!=EOF)
{
putc(ch,fp3);
}
fclose(fp1) ;
fp2=fopen("simple.c","r");
while((ch=fgetc(fp2))!=EOF)
{
putc(ch,fp3);
}
fclose(fp2) ;
fclose(fp3) ;
fp3=fopen("xyz.c","r");
printf( "The merged values of two files are :\n" ) ;
while((ch=getc(fp3))!=EOF)
{
printf("%c",ch);
}
fclose(fp3) ;
getch();
}
Output :
Enter the characters in first file below 150 size
www.codershelpline.com
Enter the characters in second file below 150 size
It is a very good site for computer knowledge.
The merged values of two files are :
www.codershelpline.com
It is a very good site for computer knowledge.
Example : A file program in C to display its own written source code on the screen as output.
#include <stdio.h>
int main()
{
FILE *fp;
int ch;
fp = fopen(__FILE__,"r");
do
{
ch = getc(fp);
putchar(ch);
}
while(c != EOF);
fclose(fp);
return 0;
}
NB :This program displays the content of file source code due to use of __FILE__ that contains the location of this C programming file in a string.
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