50.005 CSE

countline.c

We have completed the shell thus far. Now, we will implement one system program: countline. Open count_line.c inside /bin/source.

Task 5 (1%)

Task 5: Complete the implementation of countline to print out the number of lines in a file.

The countline system program accepts a pathname in args[1], open that file, and stores the number of new lines in the file inside the variable number_of_lines. Complete the following function inside count_line.c:

/*
Count the number of lines in a file
*/
int execute(char **args)
{

    int number_of_lines = 0;
    FILE *fp;

    // open file in read mode
    fp = fopen(args[1], "r");

    if (!fp)
    {
        printf("File %s cannot be found.\n", args[1]);
        return 1;
    }

    /** TASK 5  **/
    // ATTENTION: you need to implement this function from scratch and not to utilize other system program to do this
    // 1. Read the file line by line by using getline(&buffer, &size, fp)
    // 2. Loop, as long as getline() does not return -1, keeps reading and increment the count
    // 3. Store the count at number_of_lines
    // DO NOT PRINT ANYTHING TO THE OUTPUT

    /***** BEGIN ANSWER HERE *****/

    /*********************/
    fclose(fp); // close file.
    printf("%d \t %s \n", number_of_lines, args[1]);
    return 1;
}

Test Task 5

Simply recompile with make

The countline system program must work as follows. Look at these outputs carefully, and no, there’s no typos there.

If you update the .gitignore on your own, adjust the answer accordingly.

DO NOT print anything else in the console as part of your answer.

Commit Task 5

Save your changes and commit the changes:

git add ./bin/source/count_line.c
git commit -m "feat: Complete Task 5"
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