C Programming Code Examples

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Program to Replace a specified Line in a Text File



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;

    }