I want to replace all the vowels with z in string - c++

This code is replacing all the characters. Not just vowels. What am I doing wrong?
using namespace std;
bool isVowel(char);
int main() {
string fName = "";
string lName = "";
cout << "Enter first name: " << endl;
cin >> fName;
cout << "Enter last name: " << endl;
cin >> lName;
string name = fName + " " + lName;
cout << name << endl;
for(int i = 0; i < name.length(); i++) {
if(isVowel(name.at(i))) {
name[i] = 'z';
}
}
cout << name << endl;
}
bool isVowel(char c) {
if(c == 'a' || 'e' || 'i' || 'o' || 'u' || 'A' || 'O' || 'E' || 'I' || 'U') {
return true;
}
else {
return false;
}
}
I did some research online and I think my problem lies in that I am passing the character as a reference? I didn't understand how that could be...
The isVowel() function checks if the char is a vowel I think that's where the problem lies, since the program is replacing all the characters I'm assuming that function is not working.

you need to put your if statement as (c == 'a' || c == 'e' || c == 'i'..., the way it is written currently it casts all of the characters on their own as boolean expressions.

Related

Check if both characters are vowels or consonant and say yes, if they are different say no. Display vowels and consonants

I need to write a program where I enter 2 letters and it should display "Yes" if both letters are vowels or consonants. If they are different types it should display "NO".
At the end it should display the 2 entered vowels and consonants separately.
I've tried this code but it doesn't work for NO. Can you help me fix it?
#include <iostream>
using namespace std;
int main()
{
char a = 'a';
char b = 'b';
cout << "enter first charcter: " << endl;
cin >> a;
cout << "enter second character: " << endl;
cin >> b;
if ((a == 'a' || a == 'e' || a == 'i' || a == 'o' || a == 'u') && (b == 'a' || b == 'e' || b == 'i' || b == 'o' || b == 'u'))
{
cout << "YES" << endl;
}
else if ((a != 'a' || a != 'e' || a != 'i' || a != 'o' || a != 'u') && (b != 'a' || b != 'e' || b != 'i' || b != 'o' || b != 'u'))
{
cout << "YES" << endl;
}
else if ((a == 'a' || a == 'e' || a == 'i' || a == 'o' || a == 'u') && (b != 'a' || b != 'e' || b != 'i' || b != 'o' || b != 'u'))
{
cout << "NO" << endl;
}
else if ((a != 'a' || a != 'e' || a != 'i' || a != 'o' || a != 'u') && (b == 'a' || b == 'e' || b == 'i' || b == 'o' || b == 'u'))
{
cout << "NO" << endl;
}
return 0;
}
There is one issue in your second YES case and likely every consonant check. You are using logical OR, when it should be logical AND. Your character a can't be 'a' AND it cannot be 'e' AND etc. If a = 'e', it's still not the other vowels, and your big logical OR case returns true when it shouldn't.
You also repeat yourself too much. It's annoying to write, and if there is an error, like you have, it needs to be fixed in many places. Use DRY (Don't Repeat Yourself) and create a function that tells you if you have a vowel or not.
Then, you only need to explicitly check for just the YES cases or just the NO cases. Here's an example:
#include <iostream>
#include <string>
bool is_vowel(char c) {
std::string vowels = "aeiou";
return vowels.find(c) != std::string::npos;
}
int main() {
char first;
char second;
std::cout << "Letter: ";
std::cin >> first;
std::cout << "Letter: ";
std::cin >> second;
bool firstIsVowel = is_vowel(first);
bool secondIsVowel = is_vowel(second);
if ((firstIsVowel && secondIsVowel) || (!firstIsVowel && !secondIsVowel)) {
std::cout << "YES\n";
} else {
std::cout << "NO\n";
}
}
Output:
~/tmp
❯ ./a.out
Letter: a
Letter: i
YES
~/tmp
❯ ./a.out
Letter: b
Letter: c
YES
~/tmp
❯ ./a.out
Letter: a
Letter: h
NO
~/tmp took 4s
❯ ./a.out
Letter: h
Letter: a
NO
I have managed to make it work. Thank you guys!
#include <iostream>
using namespace std;
int main()
{
char a = 'a';
char b = 'b';
bool vowel1, vowel2;
cout << "enter first letter: " << endl;
cin >> a;
cout << "enter second letter: " << endl;
cin >> b;
vowel1 = (a == 'a' || a == 'e' || a == 'i' || a == 'o' || a == 'u');
vowel2 = (b == 'a' || b == 'e' || b == 'i' || b == 'o' || b == 'u');
if ((vowel1 && vowel2) || (!vowel1 && !vowel2))
{
cout << "YES" << endl;
}
else
{
cout << "NO" << endl;
}
if (vowel1)
{
cout << "vowel: " << a << endl;
}
else
{
cout << "consonant: " << a << endl;
}
if (vowel2)
{
cout << "vowel: " << b << endl;
}
else
{
cout << "consonant: " << b << endl;
}
return 0;
}

How to fix not printing any character and just count vowels and characters and read every character in a file

I just want to read every character in a file where I put characters from A TO Z but the program prints A every time and count vowels 4 and character 25 but expectation was to printing vowels 5 and characters 26 how to fix this program fixing from last 4 hours but nothing progress?
Code:
#include<iostream>
#include<fstream>
#include<string>
using namespace std;
int main() {
int i, count = 0, vowel_count = 0;
string file_name;
cout << "enter file name:";
cin >> file_name;
ifstream fin;
fin.open(file_name);
char ch;
while (!fin.eof()) {
fin.get(ch);
cout << ch;
while (fin >> ch) {
i = ch;
if ((i > 63 && i < 91) || (i > 96 && i < 123))
count++;
if (i == 'a' || ch == 'A' || ch == 'e' || ch == 'E' || ch == 'i' || ch == 'I' || ch == 'o' || ch == 'O' || ch == 'u' || ch == 'U')
vowel_count++;
}
cout << "\n No. of Characters in a File : " << count;
cout << "\n No. of vowel characters in the File : " << vowel_count;
}
fin.close();
return 0;
}
You have some really minor erros in the code, which I fixed for you.
Additionally, I added a check, if the file could be opened or not. That is the problem in most cases.
Please see below:
#include<iostream>
#include<fstream>
#include<string>
using namespace std;
int main() {
int count = 0, vowel_count = 0;
string file_name;
cout << "\nEnter file name: ";
cin >> file_name;
ifstream fin(file_name);
if (fin) {
char ch;
while (fin.get(ch)) {
cout << ch;
if ((ch >= 'A' && ch <= 'Z') || (ch > 'a' && ch <= 'z'))
count++;
if (ch == 'a' || ch == 'A' || ch == 'e' || ch == 'E' || ch == 'i' || ch == 'I' || ch == 'o' || ch == 'O' || ch == 'u' || ch == 'U')
vowel_count++;
}
fin.close();
cout << "\n No. of Characters in a File : " << count;
cout << "\n No. of vowel characters in the File : " << vowel_count;
}
else std::cerr << "\n\n*** Error. Could notopen '" << file_name << "'\n\n";
return 0;
}

How to prevent C++ buffer overflow if the user enters two or more strings separated by white spaces?

I'm a student, and I am currently working on C++ Classes. I am making a program which is supposed to ask a user to input a float point number not greater that 99.99 as a price of fuel at a gas station. I have created code that saves the user input in to a char array, and created limits so that the user can't input more than 2 dots, for example (2..2). The maximum number of characters is 5 including one dot. Now, everything works fine except for if the user enters two sets of strings before hitting enter. I have a problem because the second string messes up with other cin statements in the loop.
The code will also take the finalized char array input, and than covert it to a float variable so that the further calculations can be computed easily.
I am working on a Windows system, and Visual Studio 2017 C++.
I have tried detecting the single white space in an if/else statement, but it seems that white space is not detected as a single char array member, like this ex. else if (str[count] == ' ') , and than asking to re enter the correct input without the white space. getline() function could not work on a char array, so I couldn't discard the characters entered after including and after the white space in this way. I have tried changing the char array to a string, but still if the user inputs two or more strings separated by white space, my program keeps reading it in to cin over again.
int main()
{
int count = 0;
int lenFlag = 0, mainFlag = 0;
float result = 0;
int len;
char str[6] = "00000";
//string str ="00000";
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);
//This part will ask the user to set the price of fuel
//for the gas pump program. The programming project segment
//is from a book by Walter Savitch "Absolute C++".
while (mainFlag == 0)
{
cout << "Please enter the fuel price in dollars $";
cin >> str;
len = strlen(str);
cout << "strlen is = " << len << endl;
while (len <= 5 && mainFlag == 0)
{
count = 0, lenFlag = 0;
while (count < len && lenFlag == 0)
{
if (count == 0 && (str[count] < 48 || str[count] > 57))
{
cout << "The first input member must be a number."
"You must use a number between 0-9.\n"
"Try again: ";
cin >> str;
len = strlen(str);
lenFlag = 1;
}
else if (count > 0 && (str[count] < 48 || str[count] > 57)
&& str[count] != '.')
{
cout << "You must enter number between 0-9, or a decimal delimiter.\n"
"Try again, : ";
cin >> str;
len = strlen(str);
lenFlag = 1;
}
else if (count > 0 && (str[0] == '.' && str[1] == '.') || (str[0] == '.' && str[2] == '.') ||
(str[0] == '.' && str[3] == '.') || (str[0] == '.' && str[4] == '.') ||
(str[1] == '.' && str[2] == '.') || (str[1] == '.' && str[3] == '.') ||
(str[1] == '.' && str[4] == '.') || (str[2] == '.' && str[3] == '.') ||
(str[2] == '.' && str[4] == '.') || (str[3] == '.' && str[4] == '.'))
{
cout << "You have entered more than 1 decimal delimiter, try again: ";
cin >> str;
len = strlen(str);
lenFlag = 1;
}
else if (count > 1 && str[0] > 48 && str[0] < 58 && str[1]>47
&& str[1] < 58 && str[2]>47 && str[2] < 58)
{
cout << "Maximum number is 99.99, try again:\n";
cin >> str;
len = strlen(str);
lenFlag = 1;
}
else if (str[count] == ' ')
{
cout << "Typing whitspace is not an option!!" << endl;
cout << "Try again!!" << endl;
cin >> str;
len = strlen(str);
lenFlag = 1;
}
else if (count == len - 1 && lenFlag == 0)
{
//cout << "Main flag switches to 1!!" << endl;
mainFlag = 1;
}
count++;
}
} //while(lenCopy <= 5) loop end
if (len > 5)
{
cout << "Either non-numbers were entered, or a negative
number, or an incorrect " << endl;
cout << "number size. Enter a maximum size of 5
including a .dot for decimal number" << endl;
cout << "Maximum number is 99.99." << endl;
mainFlag = 0;
}
}//mainflag loop ends
int dotpos = 0;
for (int n = 0; n < len; n++)
{
if (str[n] == '.')
{
//dotpos = n + 1;
dotpos = len - n - 1;
cout << "dotpos = " << dotpos << endl;
}
else
{
result = result * 10 + (str[n] - '0');
//Line above is a float and character mix as a math equation.
cout << "result " << n << " = " << result << endl;
}
}
if (dotpos > 0)
result = result / (power(10, dotpos));
cout << "You have set the cost at $" << result << " per gallon." << endl;
system("pause");
return 0;
}
Occasional stack around str variable has been corrupted, and that happens when I heavily try to mess with the user input just to check if the program can crash. That's why I need to know how to clear the input after the white space. I solved the stack corruption problem by changing the char array to string, but still not the excess characters that potential users might throw down at the program.
If you must use character arrays, I highly recommend restricting the amount of characters read from the console.
The std::istream::getline() is well suited for this:
const unsigned int LIMIT = 10;
char number_as_text[LIMIT];
std::cout << "Enter a floating point number, less than 10 characters: ";
std::cin.getline(number_as_text, LIMIT);
You can then use a function like strtod to convert the string to floating point variable.
I have found one good way to solve a problem of the string buffer overflow. It uses
cin>>ws; followed by getline() function. The two need to be used in conjunction, and
than the read will be only the first string of characters and everything after the whitespace will be trashed.
cout << "Do you want to set cost in gallons or liters? "
"\nPress G for gallons or L for liters: ";
cin >> ws;
getline(cin, chooseSetCost);
while (chooseSetCost != "G" && chooseSetCost != "g" && chooseSetCost != "L" && chooseSetCost != "l")
{
cout << "Incorrect input. Try again: ";
cin >> ws;
getline(cin, chooseSetCost);
cout << "choose cost is = " << chooseSetCost << endl;
}

Fixing uninitialized local variable error

I am working on a project right now and when I try to run what I have below it gives me an error that says "uninitialized local variable 'userOption' used" on line 22, while (isValidOption(userOption) == true) {.
How do I fix that error? Thank you.
#include<iostream>
#include <string>
using namespace std;
char toupper(char ch) {
if (ch >= 'A'&&ch <= 'Z')
return(ch);
else
return(ch - 32);
}
bool isValidOption(char ch) {
if (ch == 'I' || ch == 'O' || ch == 'L' || ch == 'X')
return(true);
else
return(false);
}
char getMainOption() {
string UserInput;
char userOption;
while (isValidOption(userOption) == true) {
cout << "Choose One of the following options\n";
cout << "I--List Our Inventory\n";
cout << "O--Make an Order\n";
cout << "L--List all Orders made\n";
cout << "X--Exit\n";
cout << "Enter an option: ";
getline(cin, UserInput);
userOption = toupper(UserInput[0]);
if (!isValidOption(userOption)) {
cout << "Invalid String\n";
cout << "Enter an option: ";
getline(cin, UserInput);
userOption = toupper(UserInput[0]);
}
if (userOption == 'I')
cout << "Listing Our Inventory\n";
else if (userOption == 'O')
cout << "Make an order\n";
else if (userOption == 'L')
cout << "Listing all orders\n";
}
return userOption;
}
int main() {
char choice;
choice = getMainOption();
system("pause");
return 0;
}
What the error is saying that you're trying to read from userOption before you've ever written to it. If a variable is uninitialized, its memory contents will be full of junk left behind by other functions and it can easily cause bugs. In your case, you'll want to read input from the user into userOption before you do any logic on it. This can be done with a do-while loop:
char userOption; // not yet initialized
do {
...
cin >> userOption; // userOption gets initialized here on first loop run
} while (isValidOption(userOption)); // no need for == true, that's a tautology :-)
// NOTE: perhaps you want to loop while the input is INvalid, as in
// while (!isValidOption(userOption)); ?
A couply code-review comments I would additionally give are:
std::toupper already exists in <cctype>. Docs are here
return is not a function call and it's better to write return ch; than return(ch);
if (ch == 'I' || ch == 'O' || ch == 'L' || ch == 'X'){ return true; } else { return false; } is completely equivalent to the shorter return ch == 'I' || ch == 'O' || ch == 'L' || ch == 'X';
Also take a look at system(“pause”); - Why is it wrong?
Happy coding! Let me know if questions remain

Need to read white space and other chars C++

I have been working on this all day with no luck. Its night now and don't know what to do. My assignment is to read number of vowels, number of white spaces, and number of other characters in a user inputted sentence. I know i need to use cin.get(ch) for whitespaces, but don't know how. I also need to output the sentence to a file. Heres what I have so far:
//Get data from user
cout << "Enter your sentence on one line followed by a # to end it: " << endl;
while (cin >> noskipws >> character && character != '#')
{
character = static_cast<char>(toupper(character));
if (character == 'A' || character == 'E' || character == 'I' ||
character == 'O' || character == 'U')
{
vowelCount++;
isVowel = true;
}
if (isspace(character))
{
whiteSpace++;
}
else if (isVowel == true && isspace(character))
{
otherChars++;
}
outFile << character;
}
outFile << "vowelCount: " << vowelCount << endl;
outFile << "whiteSpace: " << whiteSpace << endl;
outFile << "otherchars: " << otherChars << endl;
This line
if (character == 'A' || 'E' || 'I' || 'O' || 'U');
Is not doing what you think. It will always return true.
you need
if (character == 'A' || character == 'E' || character == 'I' || character == 'O' || character =='U')
and remove the semicolon as well at the end of that line
Here:
while (cin >> character && character != '#')
You are skipping all white space. To prevent the operator >> from skiiping white space you need to explicitly specify this with the noskipws modifier.
while(std::cin >> std::noskipws >> character && character != '#')
Alternatively the same affect can be achieved with get
while(std::cin.get(character) && character != '#')
Next you are reading more characters outside the loop condition.
cin.get(character);
You already have a value in the variable 'character'. So remove both of these. The next iteration of the loop (in the while condition) will get the next character (as it is executed before the loop is entered).
Then fix you test as Tim pointed out.
You can then add another test for white space with:
if (std::isspace(character)) // Note #include <cctype>
{ /* STUFF */ }
#include <iostream>
using namespace std;
int main()
{
char ch;
int vowel_count = 0;
int space_count = 0;
int other_count = 0;
cout << "Enter a string ends with #: " << endl;
while(1)
{
cin.get(ch);
if(ch == '#')
{
break;
}
if(ch == 'A' || ch == 'a'
|| ch == 'E' || ch == 'e'
|| ch == 'I' || ch == 'i'
|| ch == 'O' || ch == 'o'
|| ch == 'U' || ch == 'u')
{
++vowel_count;
}
else if(ch == ' ')
{
++space_count;
}
else
{
++other_count;
}
}
cout << "Vowels: " << vowel_count << endl;
cout << "White spaces: " << space_count << endl;
cout << "Other: " << other_count << endl;
return 0;
}
No arrays
You can check for whitespace the exact same way. Common whitespace characters are space (' '), and horizontal tab ('\t'). Less-common are newline ('\n'), carriage return ('\r'), form feed ('\f') and vertical tab ('\v').
You can also use isspace from ctype.h.