I tried
char c='A';
cout<<(int)c;
But this is not for special characters and numbers I think. What's should I do?
This will kinda do it:
#include <iostream>
int main()
{
char c = 0;
for (int i = 0; i < 128; ++i,++c)
std::cout << c << " = " << i << std::endl;
// or: std::cout << c << " = " << static_cast<int>(c) << std::endl;
}
But really, it is easier (and better) to just go look at http://www.asciitable.com/ or a similar site, because everything below 32 is not printable.
Also note, only the first 127 characters are ASCII - above that we run into extended ASCII that depends on your console settings.
Related
For example if I have something like :
word="Bag"
I need output as:
B-2
a-1
g-7
Here is a more portable solution:
There are only 26 letters to consider, thus your question is easily answerable by simply providing a lookup table. There is no need to call functions such as tolower, or to assume that letters are contiguous in the collating sequence (as EBCDIC does not follow this pattern):
#include <iostream>
#include <unordered_map>
#include <string>
int main()
{
// Create the lookup table -- this could have been done in many ways,
// such as a static table of characters to values, but I chose a simple
// literal string and build the table at runtime.
const char *alpha = "aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ";
std::unordered_map<char, int> cMap;
for (int i = 0; i < 52; ++i)
cMap[alpha[i]] = i / 2; // Note there are two characters per character value,
// the lower and the upper case version of the character
// Test
std::string test = "Bag";
for ( auto& c : test)
std::cout << c << '-' << cMap[c]+1 << ' ';
std::cout << '\n';
test = "Buy";
for ( auto& c : test)
std::cout << c << '-' << cMap[c]+1 << ' ';
std::cout << '\n';
test = "Elephant";
for ( auto& c : test)
std::cout << c << '-' << cMap[c]+1 << ' ';
}
Output:
B-2 a-1 g-7
B-2 u-21 y-25
E-5 l-12 e-5 p-16 h-8 a-1 n-14 t-20
for (char ch: word) {
cout << ch << "-" << (tolower(ch) - 'a' + 1) << " ";
}
I hope the below code snippet helps :
char c = 'g'; //your character here
int position = 1 + (tolower(c))-'a': //ensure that character is in lowercase and find its position relative to 'a'
I was just reviewing my C++. I tried to do this:
#include <iostream>
using std::cout;
using std::endl;
void printStuff(int x);
int main() {
printStuff(10);
return 0;
}
void printStuff(int x) {
cout << "My favorite number is " + x << endl;
}
The problem happens in the printStuff function. When I run it, the first 10 characters from "My favorite number is ", is omitted from the output. The output is "e number is ". The number does not even show up.
The way to fix this is to do
void printStuff(int x) {
cout << "My favorite number is " << x << endl;
}
I am wondering what the computer/compiler is doing behind the scenes.
The + overloaded operator in this case is not concatenating any string since x is an integer. The output is moved by rvalue times in this case. So the first 10 characters are not printed. Check this reference.
if you will write
cout << "My favorite number is " + std::to_string(x) << endl;
it will work
It's simple pointer arithmetic. The string literal is an array or chars and will be presented as a pointer. You add 10 to the pointer telling you want to output starting from the 11th character.
There is no + operator that would convert a number into a string and concatenate it to a char array.
adding or incrementing a string doesn't increment the value it contains but it's address:
it's not problem of msvc 2015 or cout but instead it's moving in memory back/forward:
to prove to you that cout is innocent:
#include <iostream>
using std::cout;
using std::endl;
int main()
{
char* str = "My favorite number is ";
int a = 10;
for(int i(0); i < strlen(str); i++)
std::cout << str + i << std::endl;
char* ptrTxt = "Hello";
while(strlen(ptrTxt++))
std::cout << ptrTxt << std::endl;
// proving that cout is innocent:
char* str2 = str + 10; // copying from element 10 to the end of str to stre. like strncpy()
std::cout << str2 << std::endl; // cout prints what is exactly in str2
return 0;
}
Sorry guys forewarning I suck at coding but have a big project and need help!
Input: A complete Sentence.
Output: The sorted order (ASCii Chart Order) of the sentence (ignore case.)
Output a histogram for the following categories:
1) Vowels
2) Consonants
3) Punctuation
4) Capital Letters
5) LowerCase Letters
I have no clue what to even do
Since you are vague in what your issue is, I recommend the following process:
Review Requirements
Always review the requirements (assignment). If there are items you don't understand or have the same understanding as your Customer (instructor), discuss them with your Customer.
Write a simple main program.
Write a simple main or "Hello World!" program to validate your IDE and other tools. Get it working before moving on. Keep it simple.
Here's an example:
#include <iostream>
#include <cstdlib> // Maybe necessary for EXIT_SUCCESS.
int main()
{
std::cout << "Hello World!\n";
return EXIT_SUCCESS;
}
Update program to input text & validate.
Add in code to perform input, validate the input and echo to the console.
#include <iostream>
#include <cstdlib> // Maybe necessary for EXIT_SUCCESS.
#include <string>
int main()
{
std::string sentence;
do
{
std::cout << "Enter a sentence: ";
std::getline(cin, sentence);
if (sentence.empty())
{
std::cout << "\nEmpty sentence, try again.\n\n"
}
} while (sentence.empty());
std::cout << "\nYou entered: " << sentence << "\n";
// Keep the console window open until Enter key is pressed.
std::cout << "\n\nPaused. Press Enter to finish.\n";
std::cin.ignore(100000, '\n');
return EXIT_SUCCESS;
}
Add functionality, one item at a time and test.
Add code for one simple requirement, compile and test.
After it works, make a backup.
Repeat until all requirements are implemented.
For ordering the string you can use standard c qsort function. For counting vowels, consonants, punctuation... you need a simple for loop.
Here is a working example:
#include <iostream.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
int cmp(const void* pc1, const void* pc2)
{
if(*(char*)pc1 < *(char*)pc2) return -1;
if(*(char*)pc1 > *(char*)pc2) return 1;
return 0;
}
void main(int argc, char* argv[])
{
char pczInput[2000] = "A complete sentence.";
cout << endl << "Input: '" << pczInput << "'";
qsort(pczInput, strlen(pczInput), sizeof(char), cmp);
cout << endl << "Result: '" << pczInput << "'";
int iCapital = 0;
int iLowerCase = 0;
int iPunctuation = 0;
int iVowels = 0;
int iConsonants = 0;
for(unsigned int ui = 0; ui < strlen(pczInput); ++ui)
{
if(isupper(pczInput[ui])) ++iCapital;
if(islower(pczInput[ui])) ++iLowerCase;
if(ispunct(pczInput[ui])) ++iPunctuation;
if(strchr("aeiouAEIOU", pczInput[ui]) != NULL) ++iVowels;
if(strchr("bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ", pczInput[ui]) != NULL) ++iConsonants;
}
cout << endl << "Capital chars: " << iCapital;
cout << endl << "Lower case chars: " << iLowerCase;
cout << endl << "Punctuation chars: " << iPunctuation;
cout << endl << "Vowels chars: " << iVowels;
cout << endl << "Consonants chars: " << iConsonants;
cout << endl;
}
Note that I used C standard functions for counting capital, lower case and punctuation, and I had to use strchr function for counting vowels and consonants because such functions are missing in standard C library.
The output of the program is:
Input: 'A complete sentence.'
Result: ' .Acceeeeelmnnopstt'
Capital chars: 1
Lower case chars: 16
Punctuation chars: 1
Vowels chars: 7
Consonants chars: 10
I'm working on an assignment where I need to print out the ASCII table in the table format exactly like the picture below.
http://i.gyazo.com/f1a8625aad1d55585df20f4dba920830.png
I currently can't get the special words/symbols to display (8, 9, 10, 13, 27, 32, 127).
Here it is running:
http://i.gyazo.com/80c8ad48ef2993e93ef9b8feb30e53af.png
Here is my current code:
#include <iomanip>
#include <iostream>
using namespace std;
int main()
{
cout<<"ASCII TABLE:"<<endl;
cout<<endl;
for (int i = 0; i < 128; i++)
{
if (i <= 32)
cout << "|" << setw(2)
<<i
<< setw(3)
<< "^" << char (64+i) <<"|";
if (i >= 33)
cout << "|" << setw(3)
<<i
<< setw(3)
<<char (i) << "|";
if((i+1)%8 == 0) cout << endl;
}
return 0;
}
8 Back Space
9 Horizontal Tab
10 New Line
13 carriage return
27 Escape (Esc)
32 Space
127 Del
As Above these ASCII characters doesn't display any visible or printed character. That's why you might be thinking you are not getting these values.
I'm no sure what's your real problem there, but you didn't get an answer yet about how to print the special codes.
Running your programme I see that you have some minor alignment problems. If that's the problem, note that setw(3) only applies to the next element:
cout << setw(3) << "^" << char (64+i); // prints " ^A" instead of " ^A".
If you try to correct into
cout << setw(3) << "^"+ char (64+i); // ouch !!!!
you'll get undefined behaviour (garbage) because "^" is a pointer to a string and adding char(64+i) is understood as adding an offset of 64+i to this pointer. As this is a rather random address, you'll get garbage. Use a std::string instead.
The other difference I see between your programme's output and the expected result is that you don't print the code of the special chars. If that's the problem, either use a switch statement (very repetitive here), or a lot of if/else or use an associative map.
Here an alternative proposal putting all this together:
map<char, string>special{ { 8, "BS " }, { 9, "\\t " }, { 10, "\\n " }, { 13, "CR " }, { 27, "ESC" }, { 32, "SP " }, { 127, "DEL" } };
cout << "ASCII TABLE:" << endl << endl;
for (int i = 0; i < 128; i++) {
cout << "|" << setw(3)<<i<<setw(4); // setw() only applies to next
if (iscntrl(i) || isspace(i)) { // if its a control char or a space
auto it = special.find(i); // look if there's a special translation
if (it != special.end()) // if yes, use it
cout << it->second;
else cout << string("^") + char(64 + i)+ string(" "); // if not, ^x, using strings
}
else if (isprint(i)) // Sorry I'm paranoïd: but I always imagine that there could be a non printable ctrl ;-)
cout << char(i)+string(" ") ; // print normal char
cout << "|";
if ((i + 1) % 8 == 0) cout << endl;
}
Now some additional advices:
take the effort to indent
instead of manual categorization of chars, use iscntrl(), isspace(), isprint(). As long as you only use ascii, it's manageable to do like you did. But as soons as you move to internationalisation and wide chars it becomes increasinlgy cumbersome to do that whereas there are easy wide equivalents like iswcntrl(), iswspace(), iswprint().
also be rigorous on two consecutive if: If you know that only one of the two should apply, make the effort to write if ... else if these four additional lettes can save you hours of debugging later.
I would like to compare a character literal with the first element of string, to check for comments in a file. Why use a char? I want to make this into a function, which accepts a character var for the comment. I don't want to allow a string because I want to limit it to a single character in length.
With that in mind I assumed the easy way to go would be to address the character and pass it to the std::string's compare function. However this is giving me unintended results.
My code is as follows:
#include <string>
#include <iostream>
int main ( int argc, char *argv[] )
{
std::string my_string = "bob";
char my_char1 = 'a';
char my_char2 = 'b';
std::cout << "STRING : " << my_string.substr(0,1) << std::endl
<< "CHAR : " << my_char1 << std::endl;
if (my_string.substr(0,1).compare(&my_char1)==0)
std::cout << "WOW!" << std::endl;
else
std::cout << "NOPE..." << std::endl;
std::cout << "STRING : " << my_string.substr(0,1) << std::endl
<< "CHAR : " << my_char2 << std::endl;
if (my_string.substr(0,1).compare(&my_char2)==0)
std::cout << "WOW!" << std::endl;
else
std::cout << "NOPE..." << std::endl;
std::cout << "STRING : " << my_string << std::endl
<< "STRING 2 : " << "bob" << std::endl;
if (my_string.compare("bob")==0)
std::cout << "WOW!" << std::endl;
else
std::cout << "NOPE..." << std::endl;
}
Gives me...
STRING : b
CHAR : a
NOPE...
STRING : b
CHAR : b
NOPE...
STRING : bob
STRING 2 : bob
WOW!
Why does the function think the sub-string and character aren't the same. What's the shortest way to properly compare chars and std::string vars?
(a short rant to avoid reclassification of my question.... feel free to skip)
When I say shortest I mean that out of a desire for coding eloquence. Please note, this is NOT a homework question. I am a chemical engineering Ph.D candidate and am coding as part of independent research. One of my last questions was reclassified as "homework" by user msw (who also made a snide remark) when I asked about efficiency, which I considered on the border of abuse. My code may or may not be reused by others, but I'm trying to make it easy to read and maintainable. I also have a bizarre desire to make my code as efficient as possible where possible. Hence the questions on efficiency and eloquence.
Doing this:
if (my_string.substr(0,1).compare(&my_char2)==0)
Won't work because you're "tricking" the string into thinking it's getting a pointer to a null-terminated C-string. This will have weird effects up to and including crashing your program. Instead, just use normal equality to compare the first character of the string with my_char:
if (my_string[0] == my_char)
// do stuff
Why not just use the indexing operator on your string? It will return a char type.
if (my_string[0] == my_char1)
You can use the operator[] of string to compare it to a single char
// string::operator[]
#include <iostream>
#include <string>
using namespace std;
int main ()
{
string str ("Test string");
int i; char c = 't';
for (i=0; i < str.length(); i++)
{
if (c == str[i]) {
std::cout << "Equal at position i = " << i << std::endl;
}
}
return 0;
}
The behaviour of the first two calls to compare is entirely dependent on what random memory contents follows the address of each char. You are calling basic_string::compare(const char*) and the param here is assumed to be a C-String (null-terminated), not a single char. The compare() call will compare your desired char, followed by everything in memory after that char up to the next 0x00 byte, with the std::string in hand.
Otoh the << operator does have a proper overload for char input so your output does not reflect what you are actually comparing here.
Convert the decls of and b to be const char[] a = "a"; and you will get what you want to happen.
Pretty standard, strings in c++ are null-terminated; characters are not. So by using the standard compare method you're really checking if "b\0" == 'b'.
I used this and got the desired output:
if (my_string.substr(0,1).compare( 0, 1, &my_char2, 1)==0 )
std::cout << "WOW!" << std::endl;
else
std::cout << "NOPE..." << std::endl;
What this is saying is start at position 0 of the substring, use a length of 1, and compare it to my character reference with a length of 1. Reference