Week 08 Tutorial Questions

1. How are you going with assignment 1?

2. Consider the program below:

#include <stdio.h>

int main(void) {
    char str[10];
    str[0] = 'H';
    str[1] = 'i';
    printf("%s", str);
    return 0;
}

1. What will happen when the above program is compiled and executed?
2. How do you correct the program?

3. Name 3 errors in this program:

#include <stdio.h>

#define MAX_LINE 4096

int main(void) {
    char line[MAX_LINE];
    int  i;

    while (fgets(line, MAX_LINE, stdin) != NULL) {
        i = MAX_LINE;
        while (line[i] != '\n') {
            i = i - 1;
        }
        printf("the line is %d characters long\n", i);
    }
    return 0;
}

4. Strlen is a function that returns the length of a string. Write your own C function to do the same.

int myStrlen(char *string);

5. parts of a pointer

Look at this C code:

int n = 42;
int *p, *q;
p = &n;
*p = 5;
*q = 17;
q = p;
*q = 8;

Explain what does actually happen in the memory after each line in order?

6: Command line arguments

Tutor demo!

In this section we'll have a look at command line arguments and how they can be used to pass input to a C program when it is executed.

We'll be using this starter code:

#include <stdio.h>

int main(int argc, char *argv[]) {

    return 0;
}

The following diagram may be useful as a guide for explaining how command line arguments work:

Your turn!

In groups we will write pseudocode or a flowchart for one of the following programs:

Sum of Command Line Arguments: Write a C program that takes multiple integers as command-line arguments and prints their sum.

Count Characters in Command Line Arguments: Write a C program that counts the total number of characters in all the command-line arguments passed to it.

Reverse Command Line Arguments: Write a C program that prints all the command-line arguments passed to it in reverse order.

Check for Command Line Arguments: Write a C program that checks if any command-line arguments were provided except for the program name. If none were provided, print a message indicating so; otherwise, print the number of arguments.