How do I get my function to take user input and store it in an array?

Question

This project is giving me so much grief...the first issue that I'm having is that my menu forces me to input twice and then stops when I pick an option...

I really am having a hard time getting program to take user input and store it in my array so that I can pass it to my functions to be either decrypted or encrypted.

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

#define SIZE 500

int getUserChoice();
int getShift();
void getString(char buf[]);
void encrypt(char buf[], int shift);
void decrypt(char buf[], int shift);

int main()
{
    char inputBuf[SIZE] = {0};

    while ( getUserChoice() != 4)
    {

        switch (getUserChoice())
        {
            case 1:
                getShift();
                break;

            case 2:
                getString(inputBuf[SIZE]);
                encrypt(inputBuf[SIZE], getShift());

        }

    }

    return 0;
}

int getUserChoice()
{
    int userChoice = 0;

    printf("-------------------------------\n"
                 "| 1) Change Shift (default 3) |\n"
                 "| 2) Encrypt a message        |\n"
                 "| 3) Decrypt a message        |\n"
                 "| 4) Quit                     |\n"
                 "-------------------------------\n");

    printf("Option: ");
    scanf("%d", &userChoice);


    return userChoice;
}

int getShift()
{
    int shift = 3;

    do
    {
        printf("Enter new shift value: ");
        scanf("\n%d", &shift);
    } while(shift < 1 || shift > 10);

    return shift;
}

void getString(char inputBuf[])
{
    printf("Input: ");
    fgets(inputBuf, SIZE, stdin);
}

void encrypt(char inputBuf[], int shift)
{
    int i = 0;

    for (i = 0; i < inputBuf[i] && inputBuf[i] != '\0'; i++)
    {
        inputBuf[i] = inputBuf[i] + shift;

        if (inputBuf[i] = ' ')
        {
            printf("%c", ' ');
        }
        else
        {
            printf("%c", inputBuf[i]);
        }
    }
}

void decrypt(char buf[], int shift)
{

}

Please focus on a single problem in your question and make an [mre] to demonstrate it. Including sample input, expect output and actual output. — Yunnosch, Jan 20 '20 at 05:56
"my menu forces me to input twice" -- the code calls `getUserChoice()` twice.... — ad absurdum, Jan 20 '20 at 05:57
Have a look at these very helpful articles (even if they might seem cynical ) https://ericlippert.com/2014/03/21/find-a-simpler-problem/ https://ericlippert.com/2014/03/05/how-to-debug-small-programs/ http://sekrit.de/webdocs/c/beginners-guide-away-from-scanf.html https://stackoverflow.com/questions/2069367/how-to-debug-using-gdb — Yunnosch, Jan 20 '20 at 05:58

Ardent Coder · Answer 1 · 2020-01-20T11:39:51.680

Problem 1:

The first issue that I'm having is that my menu forces me to input twice

It is because you call getUserChoice twice:

First in the while header

Next in the switch header within the body of the while loop

Solution:

Define a variable like int choice = getUserChoice(); outside your while loop and use this variable for the while and switch statements instead of calling the function again and again.

Problem 2:

I really am having a hard time getting program to take user input and store it in my array so that I can pass it to my functions to be either decrypted or encrypted.

The problem lies here:

case 2:

getString(inputBuf[SIZE]);

encrypt(inputBuf[SIZE], getShift());

This is not how you pass arrays to functions.

Solution:

Replace inputBuf[SIZE] with inputBuf

Check this post to learn more about how to pass arrays to functions in C.

How do I get my function to take user input and store it in an array?

1 Answers1