Here's my problem.... In the code below, between the char guess[4] and cin >> guess my answer's element at index 0 disappeared. Anyone knows why?
while(bullCount != 4)
{
//Create the answer
char answer[4];
for(int loops = 0; loops < 4; loops++)
{
answer[loops] = createAnswerDigit(seed);
}
//Reset bullCount and cowCount from previous loop
bullCount = 0;
cowCount = 0;
cout << "Enter your guess [1000-9999]: ";
//Guess by player
char guess[4];
cout << "Answer[0]: " << answer[0] << "\n"; //Prints "Answer[0]: 4
//Retrieve guess by player
cin >> guess;
cout << "Answer[0]: " << answer[0] << "\n" //Prints "Answer[0]: "
for(int digitLoc = 3; digitLoc >= 0; digitLoc--)
{
//Do check backwards to prevent mistaking bulls for cows
int check = checkGuess(guess[digitLoc], digitLoc, answer);
if(check == cow)
{
cowCount++;
}
else if(check == bull)
{
bullCount++;
}
}
}
guess has a size of 4, however, you enter a number between 1000 - 9999 which is 4 characters long. Remember that in a string, there must be a \0 at the end of the string, so guess is 1 character short. This might be overwriting the first element of answer. Try making guess of size 5, or better yet, use std::string instead.
Clearly, the guess is an array of 4 chars. Whenever the user enters characters in range 1000-9999 it doesn't have a space for the string terminator '\0'. Thus, you need to define the array as:
char guess[5];
or you can use string implementations too
Related
I am trying to convert an input character array, to an int array in c++.
Inputs would be in a format like: 'M 911843 6', where the first value of the char array is a uppercase letter, which I convert to an ASCII value and -55.
Edit: I should also mention I just want to use the iostream library
The last value of the char array can be a letter or number also.
I want to retain the exact number value of any input in the char array, which is why I convert to an ASCII value and -48, which retains the same number, but stored as an int value:
I use the checkdigit() function to check if the char input is a number or not.
The difficulty I am facing is that the input will always have a blank space at i[1] and i[8] (if we count i[0] as the first value) - so I try to give them an int value of 0 (int of a " " is 0)
Upon several debugging attempts, I found that it is after the blank space is given a 0 value, the output in my for loop keeps outputting the wrong values, I suspect it has something to do with the isdigit() function in my for loop.
If the spaces from M 911843 6 were removed, the int output is usually fine, e.g. a char input of
M9118436 will return an int array of [22][9][1][1][8][4][3][6].
The output with spaces: [22][0][-183][-120][37][-118][-59][72][0][-55]
Ideal output: [22][0][9][1][1][8][4][3][0][6]
The code is listed below, any help or advice would be greatly appreciated, thanks!!
#include <iostream>
using namespace std;
int main() {
char a[10];
int z[10];
int i = 0;
int r; //result of the isdigit check (0 or 1)
cout << "in ";
cin >> a;
for (int i = 0; i < 10; i++) {
r = isdigit(a[i]);
if (r == 0) {
if (i==1 || i==8)
z[i] = 0;
else z[i] = int(a[i]) - 55;
}
else {
z[i] = int(a[i]) - 48;
}
}
cout << z[0] << "\n" << z[1] << "\n"<< z[2]<< "\n" << z[3] << "\n"<< z[4] << "\n"<< z[5] << "\n"<< z[6] << "\n"<< z[7]<< "\n" << z[8] << "\n"<< z[9];
return 0;
}
The problem is that cin >> a; does not read sizeof(a) characters, but up to the first space character and will terminate that with a null.
That means that you array will containt 'M', '\0' and 8 uninitialized characters. You must read the characters one at a time with unformatted reads:
for (auto& c : a) {
cin.get(c);
if (!cin) {
cerr << "Incorrect input\n";
return EXIT_FAILURE;
}
}
Just a follow on from Serge's answer which gave me a good understanding of how strings are read - I solved my problem using cin.getline() function.
I've been struggling with a homework assignment that counts the amount of instances a uppercase letters, lowercase letters, and numbers in a string. appears in a string.
I'm using a one-dimensional array with a constant size of 132 to store the entered string, and I need to use two functions. One needs to count the amount of letter occurrences in the string and the other function will execute the output something similar to above. I'm struggling most with the letter counting aspect of the program itself.
Currently, this is what my current homework resembles for the most part. It's a work in progress (of course) so errors in the code are very likely.
void LetterCount(char c_input[], int l_count)
{
// code to count letters
}
void CountOut(//not sure what should go here yet until counting gets figured out)
{
// code that handles output
}
int main()
{
const int SIZE = 132;
char CharInput[SIZE];
int LetterCount = 0;
cout << "Enter a string of up to 132 characters in size: ";
cin.getline(CharInput, SIZE);
cout << "You entered: " << CharInput << endl;
Count(CharInput);
CountOut(//not sure what goes here yet);
return 0;
}
The output would look something like:
a - 2
b - 1
c - 1
d - 0
e - 1
etc...
I've tried some experimentation with for loops to count the letters and have seen some examples of the function gcount(), but I haven't gotten anything to work. Does anyone have a suggestion as to how I would count the letters in an inputted string?
map is a very efficient data structure here
#include <iostream>
#include <map>
using namespace std;
int main(){
string str = "a boy caught 2 fireflies";
map<char, int> str_map;
for(auto x : str) ++str_map[x];
for(auto x : str_map) cout << x.first << ' ' << x.second << '\n';
}
What you want is to build a simple histogram, and it's pretty easy to do. Since what you're looking at is chars, and there can be 256 possible values of an 8-bit char (in practice your input string probably uses less, but we'll be conservative here because memory is cheap), you'll want to start with an array of 256 ints, all of them initialized to zero. Then iterate over the chars your string, and for each char in your string, use that char-value as an offset into the array(*), and simply increment that item in the array.
When you're done, all that remains is to iterate over the ints in the array and print out the ones that are non-zero, and you're done.
(*) you may want to cast the char to unsigned char before using it as an offset into the array, just to avoid any chance of it being interpreted as a negative array-index, which would result in undefined behavior (this is only an issue if your input string contains ASCII characters 128 and higher, so it may not matter in your case, but it's always good form to make code that does the right thing in all cases if you can)
As Jeremy frisner said you're building a histogram, but I disagree with the types used.
You'll want to declare your histogram like so:
size_t histogram[sizeof(char)*CHAR_BIT] = {0};
The size_t because you might overflow without it, and you need enough space if it's a nonstandard byte size.
As for printing it out. You should take a look at an ASCII table and examine which values you need to print out.
You could do it by comparing c-strings with other c-strings. But with chars and strings you can get errors like: "const *char cant be compared with strings". So you'll have to compare each c string(array) index with other c string indexes. In this program I use if statements to look for certain vowels. The way it works is that each "string alphabet_letter" is equal to it's respective lowercase and capital letters (for comparison). this is a very redundant way to do it and, if you want to count all total letters, perhaps you should try a different way, but this method doesn't use very complicated methods that require deeper understanding.
using namespace std;
int main(){
int vowel;
string A = "aA";
string E = "eE";
string I = "iI";
string O = "oO";
string U = "uU";
string str;
string str1;
bool userLength = true;
int restart = 0;
do{
cout << "Enter a string." <<endl;
getline(cin, str);
int VowelA = 0;
int VowelE = 0;
int VowelI = 0;
int VowelO = 0;
int VowelU = 0;
for(int x = 0; x < 100; x++){
if(restart == 1){
restart = 0;
x = 0;
}
if(A[0] == str[x]){
VowelA = VowelA + 1;
}
if(E[0] == str[x]){
VowelE = VowelE + 1;
}
if(I[0] == str[x]){
VowelI = VowelI + 1;
}
if(O[0] == str[x]){
VowelO = VowelO + 1;
}
if(U[0] == str[x]){
VowelU = VowelU + 1;
}
if(A[1] == str[x]){
VowelA = VowelA + 1;
}
if(E[1] == str[x]){
VowelE = VowelE + 1;
}
if(I[1] == str[x]){
VowelI = VowelI + 1;
}
if(O[1] == str[x]){
VowelO = VowelO + 1;
}
if(U[1] == str[x]){
VowelU = VowelU + 1;
}
int strL = str.length();
if(x == strL){
cout << "The original string is: " << str << endl;
cout << "Vowel A: "<< VowelA << endl;
cout << "Vowel E: "<< VowelE << endl;
cout << "Vowel I: "<< VowelI << endl;
cout << "Vowel O: "<< VowelO << endl;
cout << "Vowel U: "<< VowelU << endl;
cout << " " << endl;
}
}
char choice;
cout << "Again? " << endl;
cin >> choice;
if(choice == 'n' || choice == 'N'){userLength = false;}
if(choice == 'y' || choice =='Y')
{
restart = 1; userLength = true;
cin.clear();
cin.ignore();
}
//cout << "What string?";
//cin.get(str, sizeof(str),'\n');
}while(userLength == true);
}
/*
Sources:
printf help
http://www.cplusplus.com/reference/cstdio/printf/
This helped me with the idea of what's a vowel and whats not.
http://www.cplusplus.com/forum/general/71805/
understanding gets()
https://www.programiz.com/cpp-programming/library-function/cstdio/gets
Very important functional part of my program...Logic behind my if statements, fixed my issues with string comparison
What i needed to do was compare each part of one cstring with another c string
strstr compares two strings to see if they are alike to one another this source includes that idea-> https://www.youtube.com/watch?v=hGrKX0edRFg
so I got the idea: What is one c string was all e's, I could then compare each index for similarities with a c string whos definition was all e's.
At this point, why not just go back to standard comparison with strings? But you cant compare const chars to regular chars, so I needed to compare const chars to const chars
hence the idea sparked about the c strings that contained both e and E.
https://stackoverflow.com/questions/18794793/c-comparing-the-index-of-a-string-to-another-string
https://stackoverflow.com/questions/18794793/c-comparing-the-index-of-a-string-to-another-string
Fixed Error with using incremented numbers outside of involved forloop.
https://stackoverflow.com/questions/24117264/error-name-lookup-of-i-changed-for-iso-for-scoping-fpermissive
understanding the use of getline(cin, str_name)
https://stackoverflow.com/questions/5882872/reading-a-full-line-of-input
http://www.cplusplus.com/reference/istream/istream/getline/
http://www.cplusplus.com/forum/beginner/45169/
cin.clear - cin.ignore --fixing issue with cin buffer not accepting new input.
https://stackoverflow.com/questions/46204672/getlinecin-string-not-giving-expected-output
*/
I recently have been building a program where:
A user is asked to enter a number that will represent the size of a character array.
Then they are asked whether they will want the program to fill the values automatically, or they could press M so they could enter the values manually. They may only enter a-zA-Z values, or they will see an error.
At the end of the program, I am required to count every duplicate value and display it, for example:
An array of 5 characters consists of A;A;A;F;G;
The output should be something like:
A - 3
F - 1
G - 1
I could do this easily, however, the teacher said I may not use an additional array, but I could make a good use of a few more variables and I also can't use a switch element. I'm totally lost and I can't find a solution. I've added the code down below. I have done everything, but the counting part.
#pragma hdrstop
#pragma argsused
#include <tchar.h>
#include <iostream.h>
#include <conio.h>
#include <math.h>
#include <stdio.h>
#include <time.h>
#include <ctype.h>
void main() {
int n, i = 0;
char masiva_izvele, array[100], masiva_burts;
cout << "Enter array size: ";
cin >> n;
clrscr();
cout << "You chose an array of size " << n << endl;
cout << "\nPress M to enter array values manually\nPress A so the program could do it for you.\n\n";
cout << "Your choice (M/A): ";
cin >> masiva_izvele;
if (masiva_izvele == 'M' || masiva_izvele == 'm') {
clrscr();
for (i = 0; i < n; i++) {
do {
cout << "Enter " << i + 1 << " array element: ";
flushall();
cin >> masiva_burts;
cout << endl << int(masiva_burts);
if (isalpha(masiva_burts)) {
clrscr();
array[i] = masiva_burts;
}
else {
clrscr();
cout << "Unacceptable value, please enter a value from the alphabet!\n\n";
}
}
while (!isalpha(masiva_burts));
}
}
else if (masiva_izvele == 'A' || masiva_izvele == 'a') {
clrscr();
for (i = 0; i < n; i++) {
array[i] = rand() % 25 + 65;
}
}
clrscr();
cout << "Masivs ir izveidots! \nArray size is " << n <<
"\nArray consists of following elements:\n\n";
for (i = 0; i < n; i++) {
cout << array[i] << "\t";
}
cout << "\n\nPress any key to view the amount of every element in array.";
//The whole thing I miss goes here, teacher said I would need two for loops but I can't seem to find the solution.
getch();
}
I would be very thankful for a solution so I could move on and forgive my C++ amateur-ness as I've picked this language up just a few days ago.
Thanks.
EDIT: Edited title to suit the actual problem, as suggested in comments.
One possible way is to sort the array, and then iterate over it counting the current letter. When the letter changes (for example from 'A' to 'F' as in your example) print the letter and the count. Reset the counter and continue counting the next character.
The main loop should run foreach character in your string.
The secondary loop should run each time the main "passes by" to check if the current letter is in array. If it's there, then ++.
Add the array char chars[52] and count chars in this array. Then print out chars corresponding to the array, which count is more than 1.
std::unordered_map<char, int> chars;
...
char c = ...;
if ('A' <= c && c <= 'Z')
++chars[c];
else if ('a' <= c && c <= 'z')
++chars[c];
else
// unexpected char
...
for (const auto p : chars)
std::cout << p.first << ": " << p.second << " ";
Assuming upper and lower case letters are considered to be equal (otherwise, you need an array twice the size as the one proposed:
std::array<unsigned int, 26> counts; //!!!
// get number of characters to read
for(unsigned int i = 0; i < charactersToRead; ++i)
{
char c; // get a random value or read from console
// range check, calculate value in range [0; 25] from letter...
// now the trick: just do not store the value in an array,
// evaluate it d i r e c t l y instead:
++counts[c];
}
// no a d d i t i o n a l array so far...
char c = 'a';
for(auto n : counts)
{
if(n > 0) // this can happen now...
{
// output c and n appropriately!
}
++c; // only works on character sets without gaps in between [a; z]!
// special handling required if upper and lower case not considered equal!
}
Side note: (see CiaPan's comment to the question): If only true duplicates to be counted, must be if(n > 1) within last loop!
This is part of a greater code for reading an input file word-for-word, then printing the words in reverse order. It uses a string array called words[] to store, word-by-word, the char strings from an input file earlier in the program:
//print to screen
for (int i = MAXSIZE; i >= 0; i--)
{
cout << words[i] << " ";
}
Test input file contents:
This is my test file. I hope this works.
Output is just "works. " repeating on and on.
Why is the i-- apparently never happening?
EDIT: Everything from my code. I'm on a bit of a time crunch here, to say the least. MAXSIZE=1024 part of lab prompt. Can't use vectors or reverse; seen that all over, but it's off limits for this lab. New to programming, so if you could refrain from being condescending, that'd be great. Just trying to get this to work. The reading input.txt and print to screen bit works fine. Output portion is utter fail and I don't know why. Can someone just tell me why instead of insulting me, thanks?
//Kristen Korz
//CIS 22A
//This program reads an input file and writes the words in reverse order to an output file.
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
//create and link input...
ifstream inputFile;
inputFile.open("input.txt");
//...and output files
ofstream outputFile;
outputFile.open("output.txt");
//error message for file open fail
if (inputFile.fail())
cout << "Error opening the file.\n";
//constant for max size
const int MAXSIZE = 1024;
//string array and temporary-use string
string words[MAXSIZE];
string str; //note: variables will be used for output loops too
//read words from input file
for (int i = 0; (inputFile >> str) && (i < MAXSIZE); ++i)
{
words[i] = str;
//for showing in terminal if read correctly
cout << words[i] << " ";
}
inputFile.close();
cout << endl;
//something wrong with for loop resulting in i apparently not updating
for (int i = MAXSIZE; (outputFile << str) && (i >= 0); --i)
{
words[i] = str;
//for showing in terminal if written correctly
cout << words[i] << " ";
}
outputFile.close();
cout << endl;
system("pause");
return 0;
}
For output with i also printed, my cout statements in the for-loops say:
cout << words[i] << " " << i << " ";
Giving terminal output:
This 0 is 1 my 2 test 3 file. 4 I 5 hope 6 this 7 works. 8
works. 1023 works. 1022 works. 1021 (lots of repeats of works. followed by decrementing numbers) works. 3 works. 2 works. 1 works. 0
Your output loop does:
words[i] = str;
for every iteration. str still holds the value of the last string you input, so this sets every member of words to be the same string. Since your last input string was "works", this explains why you output "works" every time.
It should work better if you just remove that line. Also, start from MAXSIZE - 1. The valid indices of the array are 0 through MAXSIZE-1. Your out-of-bounds access causes undefined behaviour, although apparently in this instance it had no effect.
However if your input only has 8 words as you suggest, then outputting 1024 words will give you a lot of blank space. Consider starting the output from where i got up to, instead of MAXSIZE - 1.
At the part marked as not working (the second for loop), str is being read from but it is never changed to anything else in that loop, so it repeats the last word. i is being updated, the problem is that str is not being updated.
The other issue is that you are trying to access an element past the end of the array, as WhozCraig and Velthune discussed in their answers. You need to properly figure out what you want to do with words in your second for loop. This is key. Also, you need to store where the array you read in ends.
Viewing WhozCraig's link, if you have:
const int MAXSIZE = 1024;
string words[MAXSIZE];
for (int i = MAXSIZE; i >= 0; i--) {
cout << words[i] << " ";
}
You have a string that from 0..1023.
Accessing words[1024] is potentially dangerous.
For iterate correctly your string do:
for (int i = MAXSIZE - 1; i >= 0; --i) {
cout << words[i] << " ";
}
By the way, when you fill words, add a control:
for (int i = 0; (inputFile >> str) && (i < MAXSIZE); ++i)) {
if(str.size() <= MAXSIZE) {
words[i] = str;
}
}
update
Be sure that your string in file:
"This is my test file. I hope this works. "
doesn't end with a space. To be sure, test adding "EOF" to your string:
"This is my test file. I hope this works.EOF"
Other, do your loop in this way:
int i = 0;
while(inputFile.good() && i < MAXSIZE) {
std::string word << inputFile;
if(!word.empty())
words[i] = str;
//for showing in terminal if read correctly
cout << words[i] << " ";
}
The problem why you get a lot of "works" here is:
After this piece of codes:
//read words from input file
for (int i = 0; (inputFile >> str) && (i < MAXSIZE); ++i)
{
words[i] = str;
//for showing in terminal if read correctly
cout << words[i] << " ";
}
inputFile.close();
cout << endl;
//str = "works";
The values of variable str is works.
After that, you set every elements in words by str. So every elements in the words now are the same value works.
for (int i = MAXSIZE; (outputFile << str) && (i >= 0); --i)
{
words[i] = str;//=="works"
//for showing in terminal if written correctly
cout << words[i] << " ";
}
outputFile.close();
cout << endl;
How can I write a program that reads in, a collection of characters from the key board and outputs them to the console. Data is input at random, but output selectively. Only unique characters are displayed at the console. Therefore, every character should be displayed once, no matter how many times it appears in the array.
For example, if an array
Char letterArray[ ] = {B,C,C,X,Y,U,U,U};
The output should be:
B,C,X,Y,U
This is what I have done so far...
char myArray [500];
int count = 0;
int entered = 0;
char num;
while (entered < 8)
{
cout << "\nEnter a Character:";
cin >> num;
bool duplicate = false;
entered++;
for (int i = 0; i < 8; i++)
{
if (myArray[i] == num)
duplicate=true;
}
if (!duplicate)
{
myArray[count] = num;
count++;
} // end if
else
cout << num << " character has already been entered\n\n";
// prints the list of values
cout<<"The final Array Contains:\n";
for (int i = 0; i < count; i++)
{
cout << myArray[i] << " ";
}
}
I believe you could make use of std::set<>.
"Sets are a kind of associative container that stores unique elements <...> elements in a set are always sorted from lower to higher following a specific strict weak ordering criterion set"
Looking through your code...
char myArray [500];
Why 500? You never use more than 8.
char num;
Confusing naming. Most programmers would expect a variable named num to be a numeric type (e.g. int or float).
while (entered < 8)
Consider replacing 8 with a constant (e.g. const int kMaxEntered = 8;).
cin >> num;
cin might be line-buffered; i.e. it does nothing until a whole line is entered.
for (int i = 0; i < 8; i++)
{
if (myArray[i] == num)
duplicate=true;
}
You're accessing uninitialized elements of myArray. Hint: your loop size should not be 8.
Consider using continue; if you find a duplicate.
if (!duplicate)
{
myArray[count] = num;
count++;
} // end if
else
cout << num << " character has already been entered\n\n";
Your // end if comment is incorrect. The if isn't ended until the else is done.
You may want to add braces around the else clause, or remove the braces from the if clause by combining its two lines into the one-line myArray[count++] = num;.
// prints the list of values
cout<<"The final Array Contains:\n";
for (int i = 0; i < count; i++)
{
cout << myArray[i] << " ";
}
You're printing the list every time you get a single input?
Don't use \n in text to cout unless you specifically want to micromanage buffering. Instead, use endl. Also, always put spaces around binary operators like << and don't randomly capitalize words:
cout << "The final array contains:" << endl;
for (int i = 0; i < count; i++)
cout << myArray[i] << " ";
cout << endl;
It would be much more efficient to create an array of size 128 (assuming you are dealing with ASCII) that is initialized with false. Every time you get a character, check its ASCII value and if the array is true on that value you don't print it. After that, update the value of the array on the character value to true. Something like:
bool *seenArray = new bool[128]();
void onkey(char input) {
if(((int)input) < 0) return;
if (!seenArray[(int)input]) {
myArray[count] = input;
count++;
seenArray[(int)input] = true;
}
}