StringCharacterFrequency.cpp

#include<bits/stdc++.h>

using namespace std;

class strg {
    string s;
public:
    void enter() {
        cout << "\nEnter a string: ";
        getline(cin, s);
    }

    void freq() {
        int c = 0, count[26] = {0};
        while (s[c] != '\0') {
            if (s[c] >= 'a' && s[c] <= 'z') {
                count[s[c] - 'a']++;
            }
            c++;
        }
        for (int i = 0; i < 26; i++) {
            if (count[i] != 0)
                cout << "\n" << (char) (i + 'a') << " occurs " << count[i] << " times in the string." << endl;
        }
    }

    void palindrome() {
        int i, j, len, flag = 1;
        for (len = 0; s[len] != '\0'; ++len);
        for (i = 0, j = len - 1; i < len / 2; i++, --j) {
            if (s[i] != s[j]) {
                flag = 0;
                break;
            }
        }
        if (flag) {
            cout << "\nThe string is a palindrome." << endl;
        } else {
            cout << "\nThe string is not a palindrome." << endl;
        }
    }

    void chardelete() {
        string b;
        b = s;
        char ch;
        cout << "\nEnter what character you want to delete: ";
        cin >> ch;
        cout << "\nThe string after deleting the character from the string is: ";
        for (int i = 0; b[i] != '\0'; i++) {
            if (b[i] == ch) {
                b.erase(b.begin() + i);
            }
            cout << b[i];
        }
        cout << endl;
    }

    void substring() {
        string ca, cb;
        ca = s;
        int start, length;
        cout << "\nEnter starting index for replacement: ";
        cin >> start;
        cout << "\nEnter length of the string to be replaced: ";
        cin >> length;
        int v = (length + start);
        cout << "\nEnter string for replacement: ";
        cin >> cb;
        cout << "\nNew string is:";
        ca.replace(start, v, cb);
        cout << ca;
    }
};

int main() {
    strg a;
    a.enter();
    a.freq();
    a.palindrome();
    a.chardelete();
    a.substring();
    return 0;
}