C Program to Replace a Specific Line in a Text File

This C Program replace a specified line in a text file.

Here is source code of the C Program to replace a specified line in a text file. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C Program to Replace a specified Line in a Text File

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
int main(void)
```
```
{
```
```
    FILE *fileptr1, *fileptr2;
```
```
    char filechar[40];
```
```
    char c;
```
```
    int delete_line, temp = 1;
```
```
 
```
```
    printf("Enter file name: ");
```
```
    scanf("%s", filechar);
```
```
    fileptr1 = fopen(filechar, "r");
```
```
    c = getc(fileptr1);
```
```
    //print the contents of file .
```
```
    while (c != EOF)
```
```
    {
```
```
        printf("%c", c);
```
```
        c = getc(fileptr1);
```
```
    }
```

    printf(" \n Enter line number to be deleted and replaced");

```
    scanf("%d", &delete_line);
```
```
    //take fileptr1 to start point.
```
```
    rewind(fileptr1);
```
```
    //open replica.c in write mode
```
```
    fileptr2 = fopen("replica.c", "w");
```
```
    c = getc(fileptr1);
```
```
    while (c != EOF)
```
```
    {
```
```
        if (c == 'n')
```
```
        {
```
```
            temp++;
```
```
        }
```

        //till the line to be deleted comes,copy the content to other

```
        if (temp != delete_line)
```
```
        {
```
```
            putc(c, fileptr2);
```
```
        }
```
```
        else
```
```
        {
```

            while ((c = getc(fileptr1)) != 'n')

```
            {
```
```
            }
```

            //read and skip the line ask for new text

```
            printf("Enter new text");
```
```
            //flush the input stream
```
```
            fflush(stdin);
```
```
            putc('n', fileptr2);
```
```
            //put 'n' in new file
```

            while ((c = getchar()) != 'n')

```
                putc(c, fileptr2);
```

            //take the data from user and place it in new file

```
            fputs("n", fileptr2);
```
```
            temp++;
```
```
        }
```

        //continue this till EOF is encountered

```
        c = getc(fileptr1);
```
```
    }
```
```
    fclose(fileptr1);
```
```
    fclose(fileptr2);
```
```
    remove(filechar);
```
```
    rename("replica.c", filechar);
```
```
    fileptr1 = fopen(filechar, "r");
```
```
    //reads the character from file
```
```
    c = getc(fileptr1);
```

    //until last character of file is encountered

```
    while (c != EOF)
```
```
    {
```
```
        printf("%c", c);
```
```
        //all characters are printed
```
```
        c = getc(fileptr1);
```
```
    }
```
```
    fclose(fileptr1);
```
```
    return 0;
```
```
}
```

$ cc pgm48.c
$ a.out
Enter file name: pgm3.c
/*
 * C Program to Convert Octal to Decimal
 */
 
#include <stdio.h>
#include <math.h>
 
int main()
{
 
    long int octal, decimal = 0;
    int i = 0;
 
    printf("Enter any octal number: ");
    scanf("%ld", &octal);
    while (octal != 0)
    {
        decimal =  decimal +(octal % 10)* pow(8, i++);
        octal = octal / 10;
    }
    printf("Equivalent decimal value: %ld",decimal);
    return 0;
}
 
Enter line number to be deleted and replaced 13 replaced
Enter new text
/*
 * C Program to Convert Octal to Decimal
 */
 
#include <stdio.h>
#include <math.h>
 
int main()
{
 
    long int octal, decimal = 0;
    int i = 0;
 replaced
    printf("Enter any octal number: ");
    scanf("%ld", &octal);
    while (octal != 0)
    {
        decimal =  decimal +(octal % 10)* pow(8, i++);
        octal = octal / 10;
    }
    printf("Equivalent decimal value: %ld",decimal);
    return 0;
}

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