c++ program for :

Question

accept a string and print the count of each characters in a string which consists of numbers,alphabets,special characters

Answer 1

I understand you.
I can give you some hints to warm up your mind.
Ask yourself these questions:

1. How many printable ASCII character do we have ¹ and what is the numeric range of them ²?

printable ASCII chars = { ' ', '!', '"', '#', '#x27;, ..., '{', '|', '}', '~' }

2. How should a string break down to its building blocks? Considering that the string is a sequence of characters, then the individual chars can be accessed by the bracket operator?

string s = "Hello!";
cout << "First character of s is: " << s[0];

3. What about the last char? Is there a method to retrieve the length of a string?

int length_of_s = s.length();
cout << "Last char of s is: " << s[length_of_s - 1];

4. Can I use a loop for traversing the whole string and extracting each char?

char current_char;
for (unsigned i = 0; i < size_of_s; ++i) {
current_char = s[i];
}

5. How to "store" the number of each char in the whole string, now? What's the easiest way to do so? Can an array help me? How should I construct an array to hold printable chars? how many cells do I require to set aside for that? Are 128 cells suffice ¹?

int table[128] = {0}; // char type is a subset of int type. There's a good reason for choosing the table type int instead of char. all cells set to zero.

6. How to establish a link between all these items to make it work? What construct do I have to add to the above for loop's body or change?

for (unsigned i = 0; i < size_of_s; ++i) {

int ascii_value_of_char = s[i];
// H -> 72
// e -> 101
// l -> 108
// o -> 111

++table[ascii_value_of_char]; // increase the content of the cell indicated by the current ascii value

}

[To be continued...]

_____
¹ http://www.maestramarta.it/coding-codice-binario/ascii-0-127/
² http://facweb.cs.depaul.edu/sjost/it212/documents/ascii-pr.htm

Answer 2

Have you tried to come up with a solution?
If not please take your time and do that, otherwise, ours won't help you to understand the problem and as a matter of fact, you won't appreciate the achievement of a decent solution.

Answer 3

[...Continue]

7. How should I print out the desired result? (I'm running out of juice! 8D)

for (int i = 32; i < 128; ++i) {
if (table[i] == 0)
continue;
else
std::cout << "number of '" << (char)i << "' character is: " << table[i] << std::endl;
}

8. How does it look all together?! (Bonus) 8D

#include <iostream>
#include <string>

int main()
{
const int TableLength = 128;
const int PrintableStart = 32;

int table[TableLength] = {0};
std::string s = "Hello!";

for (unsigned i = 0; i < s.length(); ++i) {
int ascii_value_of_char = s[i];
++table[ascii_value_of_char];
}

for (int i = PrintableStart; i < TableLength; ++i) {
if (table[i] == 0)
continue;
else
std::cout << "number of '" << (char)i << "' character is: " << table[i] << std::endl;
}

}

Output:
number of '!' character is: 1
number of 'H' character is: 1
number of 'e' character is: 1
number of 'l' character is: 2
number of 'o' character is: 1

Answer 4

Thank you so much I will check it out 😃

Answer 5

The explanation is very clear😊

Answer 6

Thank you
I tried it
I am not getting an idea how to print the characters without repeating them