Simple C Programs Based On File Handling.

**Program which replaces a particular character in the file with another character. In case the character repeats then only the last occurrence is replaced.**

#include<stdio.h>

#include<conio.h>

int main()

{

    FILE *fp;

    int pos;    //Opening the file in the write mode.

    fp=fopen("srecord.txt","w");

    if(fp==NULL)

    printf("\nError");

    char str[]="Sample String in a File";

    char c,c1,c2;  //Writing to the file using fputs

    fputs(str,fp);

    fflush(fp);

    printf("\nEnter character you want to search");

    scanf("%c",&c1);

    printf("\nEnter character you want to modify");

    fflush(stdin);

    scanf("%c",&c2);   //Taking the file pointer to the beginning of the file

    rewind(fp);   //Reading the file character by character till the EOF.

    while((fscanf(fp,"%c",&c))!=EOF)

    {

    //Store the position with the match

    if(c==c1)

    pos=ftell(fp)-1;

    }

    //Take the file pointer to the beginning.

    rewind(fp);   //Position the file pointer at the replacement point

    fseek(fp,pos,0);     //Printing other character at its place

    fprintf(fp,"%c",c2);   //Taking the pointer to the beginning

    rewind(fp);

    printf("\nContents of the file are ");   //Printing the contents on the screen

    while((fscanf(fp,"%s",str))!=EOF)

    printf("%s ",str);    

    fclose(fp);    //Closing the file.

    getch();

}    

Program 2: Reading and writing data in to the file using structure.

#include<stdio.h>

#include<conio.h>

#include<stdlib.h>  //Creating structure

struct student

{

char name[20];

int rollno;

float marks;

};

void Write();

void Read();  

FILE *fp;   //File stream pointer

int count;

//Structure Variable which will be read and written

struct student s1;

int main()

{

int ch;

while(1)

{

printf("\n1.Write Data");

printf("\n2.Read Data");

printf("\n3.Exit");

printf("\nChoice");

scanf("%d",&ch);

if(ch==1)

{

Write();

}

if(ch==2)

{

Read();

}

if(ch==3)

exit(0);

}

}

void Write()

{

count++;

//Open the file in a+ mode so as to read and write data to the file

fp=fopen("K1201.txt","a+");

printf("\nName:- ");

fflush(stdin);

gets(s1.name);

printf("\nRoll Number:- ");

scanf("%d",&s1.rollno);

printf("\nMarks:- ");

scanf("%f",&s1.marks);

//Use the fwrite function to write the data to the file

fwrite(&s1,sizeof(struct student),1,fp);

//Close the file after writing the data

fclose(fp);

}

void Read()

{

int i;

//Open the file in a+ mode so that we can read and write the data

fp=fopen("K1201.txt","a+");

for(i=0;i<count;i++)

{

//Read all the records from the file one by one. We are reading an entire

//structure variable one at a time

fread(&s1,sizeof(struct student),1,fp);

printf("\nName:- %s",s1.name);

printf("\nRoll Number:- %d",s1.rollno);

printf("\nMarks:- %f",s1.marks);

}

//Closing the file

fclose(fp);

}

From site : http://ctechrockz.blogspot.com/

On Software Systems.

 A Brief Discussion About Software Systems:

System software consists of programs that which manages the hardware resources of a computer. And it performs the required tasks. These programs are further classified to three categories:

System support, System development, and the Operating system.

Operating Systems:

The Operating systems provides services such as user interface, files, and data base access. And also interface to  communication systems such as Internet Protocols. The primary purpose of this operating system's software is to keep the system operating in an efficient manner.

System Support:

The System software provides system utilities and other operating services. Examples are of sort programs and disk format programs. Operating services consists of programs that provide performance statistics for the operational staff and security monitors to protect the system and the data.

System Development Software:

The System development software includes the language translation that convert programs into machine language for execution, debugging tools to ensure that the programs are error free and Computer Assisted Software Engineering(CASE)systems.

From site : http://ctechrockz.blogspot.com/

On Software Applications.

Software Applications:

Same as like System Software's, Application Software is also classified into two categories:

General Purpose Software, and the Application Specific Software.

General Purpose Software:

It is purchased from Software developers and it can be used for more than one application. Word processors, Data Base Management Systems, and Computer Aided Designing or Drafting Systems comes under these software systems.

Application Specific Software:

It can be used only for its intended or achieving purposes. A general ledger(i.e. a book in which a company or organization write downs the amount of money it spends and receives) system used by accounts and a material requirement planning systems used by a manufacturing organization are examples of Application Specific Software. They can be used only for the task for which they are designed.

From site : http://ctechrockz.blogspot.com/