lab.c

/*****************************************************************//**
 * \file   lab.c
 * \brief  Lab 6 on C-Style strings (character array)
 *
 * \author Xuhua Huang
 * \date   February 2021
 *********************************************************************/

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/**
 * @brief Function prototype for clear function.
 * Empty the input buffer.
 */
void clear(void);

int main(void)
{
    // Q1 first name, last name and concatenate to full name using scanf_s and strcat_s
    char strFirstName[20] = { " " }; // declaring three empty strings for further usage
    char strLastName[20] = { " " };  // it looks like I have to give this char array a size, or it will simply crash. Is it true?
    char strFullName[40] = { " " };

    printf("Please enter your first name.\n");
    scanf_s("%s", &strFirstName, (unsigned int)sizeof(strFirstName)); // it might means there is enough room for this input to go in
    clear();
    puts(strFirstName); //testing purpose. verify that the string is written in the memory

    printf("Please enter your last name.\n");
    scanf_s("%s", &strLastName, (unsigned int)sizeof(strLastName));
    clear();
    puts(strLastName); //do NOT use quotation marks in puts or it prints the content between them

    strcat_s(strFullName, sizeof(strFullName), strFirstName); // add string first name to string first name
    strcat_s(strFullName, sizeof(strFullName), " "); // add a space between string first name and last name
    strcat_s(strFullName, sizeof(strFullName), strLastName); // add string last name to full name
    puts(strFullName); // prints the full name string with added last name

    char strFullNamev2[40] = { " " };
    strcpy_s(strFullName, sizeof(strFullName), strFullNamev2); // instructor specify "the string in question 1", strFullName will be overwritten in Q2
    // therefore, the content of the string is copied to another new string

    // Q2 using sprintf_s instead of strcat_S
    // three strings were declared before. overwrite instead of creating new ones
    printf("Please enter your first name.\n");
    scanf_s("%s", &strFirstName, (unsigned int)sizeof(strFirstName)); // it might means there is enough room for this input to go in
    clear(); //calling the clear function to clear the input stream
    puts(strFirstName); // this line is here for testing purpose only, same applies for the next one in this section

    printf("Please enter your last name.\n");
    scanf_s("%s", &strLastName, (unsigned int)sizeof(strLastName));
    clear();
    puts(strLastName); //do NOT use quotation marks in puts or it prints the content between them

    sprintf_s(strFullName, sizeof(strFullName), "%s %s", strFirstName, strLastName);
    // %s are place holders, double quotation marks include the space between two strings

    puts(strFullName); // prints the full name string with added last name

    // Q3 prints the length of the string strFullName
    int length = strlen(strFullNamev2) - 1;
    printf("\nThe length of your full name is %d(including spaces).\n", length);
    // QUESTION: How come there is always an extra space before my first name??? I have to go with -1 because of this
    // reply: it is counting the space between first name and last name

    // Q4 get a string from the user and convert it to all capital letters
    char newStr[999] = { " " }; // declaring a new string
    printf("\nYou just entered another section of this program xD\n\nPlease enter the string you would like to convert to upper cases.\n");
    gets_s(newStr, sizeof(newStr)); // using gets_s instead of scanf_s
    //scanf_s("%s", &newStr, sizeof(newStr)); // reference

    for (int i = 0; i < strlen(newStr); i++) // strlen() function determines the times the loop will run
    {
        newStr[i] = toupper(newStr[i]);
    } // this for loop OVERWRITES the string with upper case letters one character at a time
    puts(newStr); // this line prints the ENTIRE newStr

    // Q5 Write a program that compares “Heads" with input from a user which should be either "Heads" or Tails" (use strcmp()).
    // condition: if the user enters "Heads", print "You win" otherwise print "You lose".

    char strFixed[] = { "Heads" };
    puts(strFixed); // this line is here for testing purpose only
    char userInputStr[20] = { " " }; // declaring an empty array for further usage
    printf("\nWhat option would you use to display the first ten lines of a file?\nEnter 'Heads' or 'Tails'(case sensitive).\n\n");
    gets_s(userInputStr, sizeof(userInputStr)); // grab an input from the user and store

    int rtnValue = strcmp(userInputStr, strFixed);
    if (rtnValue == 0) // i didn't forget double equal this time
        printf("You win!\n");
    else
        printf("You entered the wrong answer;");
    //what does this line do?? strcmp(userInputStr, sizeof(userInputStr), strFixed); it did not give me an error

    // Q6 Have the user enter a string of numbers (store the input into a character array)
    // Write a program that converts the string into an integer (Use atoi() ). Print the string and the integer.  

    char strToInt[999] = { " " };
    printf("Please enter the string that you like to convert to an integer.\n");
    gets_s(strToInt, sizeof(strToInt)); // grab input and store

    int num = atoi(strToInt);

    printf_s("The resultant number is %d.\n", num);
    puts(strToInt); // for testing purpose only


    // function atoi() - convert string array to a number (integer)
    // since math cannot be performed on numbers that are characters
    //char numstr[] = { "5123" };
    //int number = atoi(numstr);
    ////printf("number as string %d\n", atoi(numstr));
    //printf("%d\n", number);

    // Q7 Have the user enter an integer.  Write a program that converts the integer into a string (Use sprintf() )
    //Print the string and the integer.  
    int num2;
    printf("Enter a number that you would like to convert to string.\n");
    scanf_s("%d", &num2);

    char numToStr[999] = { " " };
    sprintf_s(numToStr, sizeof(numToStr), "%d", num2);
    puts(numToStr);

    // convert integer to string using sprintf
    /*int num = 20;
    sprintf_s(numstr, sizeof(numstr), "%d", num);
    puts(numstr);
    */

    // Q8 Write a program that asks the user to enter a string (use puts/gets).
    // Use a switch statement to identify a vowel and count the number of A, E, I , O and U letters that were entered.  It should not be case sensitive.
    int conf = 0;
    do
    {
        char userInput[999] = { " " };
        printf("Plese enter the string in which you would like yo count the vowel.\n");
        gets_s(userInput, sizeof(userInput));
        printf("\nThe string you just entered is listed as the following:\n");
        puts(userInput);

        int vowelCount = 0; // int declaration has to be outside of the switch cases
        for (int i = 0; i < strlen(userInput) - 1; i++)
        {
            char match = userInput[i];
            switch (match)
            {
            case 'A': // all the cases that I need to count without breaking
            case 'a': // I want the string go through each case
            case 'E':
            case 'e':
            case 'I':
            case 'i':
            case 'O':
            case 'o':
            case 'U':
            case 'u':
                vowelCount++;
            }
        }
        printf("The number of vowel characters in the string you just typed is %d.\n\n", vowelCount + 1); // +1 to match the right count
        printf("Would you like to continue?\nPlease enter 0 if you would like to continue and 1 to quit.\n");
        scanf_s("%d", &conf);
        clear(); // the repeating part wasn't working until I clear it. 
                //I assume it's the input stream thing again, it was skipping the gets_s part with an error message

    } while (conf == 0); // I remember to put double equal signs this time xD


    // Q bonus 1 string to Morse code
    int run = 0;
    do
    {
        char strToMorse[20] = { "" };
        //char strMorseCode[80] = { "" }; // for converted Morse Code

        printf("Please enter the string you would like to convert to Morse Code.\n");
        gets_s(strToMorse, sizeof(strToMorse));
        //puts(strToMorse); // testing purpose only, it automatically starts a new line
        //clear();

        for (int j = 0; j < strlen(strToMorse); j++)
        {
            switch (strToMorse[j])
            {
            case 'A':
                puts(".-");
                break;
            case 'B':
                puts("-...");
                break;
                /*case 'C':

                case 'D':

                case 'E':

                case 'F':

                case 'G':

                case 'H':

                case 'I':

                case 'J':

                case 'K':

                case 'L':

                case 'M':

                case 'N':

                case 'O':

                case 'P':

                case 'Q':

                case 'R':

                case 'S':

                case 'T':

                case 'U':

                case 'V':

                case 'W':

                case 'X':

                case 'Y':

                case 'Z':
                */
                //puts(strMorseCode);
            /*
            case 0:

            case 1:

            case 2:

            case 3:

            case 4:

            case 5:

            case 6:

            case 7:

            case 8:

            case 9:

                printf("Trial.\n");
            */
            }
        }
        printf("%d\n", (int)strlen(strToMorse));

        printf("Would you like to continue?\nEnter 0 for yes and 1 to quit.\n");
        scanf_s("%d", &run);
        clear(); // same idea as the above

    } while (run == 0);

    int numbers[5] = { 2, 4, 6, 8, 10 };
    printf("%d", *numbers);

    return 0;
}

/**
 * @brief Define function to empty the input buffer.
 * receives nothing and returns nothing
 */
void clear(void)
{
    while (getchar() != '\n');
}