Ass3_StringOperations.cpp

#include <iostream>
#include <cstring>
using namespace std;

class Str {
    char s[100];

public:

    void input(){
        cout<<"Enter string: ";
        cin>>s;
    }

    // 1. Frequency
    void freq(){
        char ch;
        int count=0;

        cout<<"Enter character: ";
        cin>>ch;

        for(int i=0; s[i]!='\0'; i++){
            if(s[i]==ch)
                count++;
        }

        cout<<"Frequency = "<<count<<endl;
    }

    // 2. Substring
    void substr(){
        int pos,len;
        char temp[100];

        cout<<"Enter start and length: ";
        cin>>pos>>len;

        int j=0;
        for(int i=pos; i<pos+len && s[i]!='\0'; i++){
            temp[j++] = s[i];
        }
        temp[j]='\0';

        cout<<"Substring = "<<temp<<endl;
    }

    // 3. Remove character
    void removeChar(){
        char ch;
        cout<<"Enter character: ";
        cin>>ch;

        int j=0;
        for(int i=0; s[i]!='\0'; i++){
            if(s[i]!=ch){
                s[j++] = s[i];
            }
        }
        s[j]='\0';

        cout<<"Updated string = "<<s<<endl;
    }

    // 4. Replace substring
    void replace(){
        char w[50], x[50], result[100];
        cout<<"Enter substring w: ";
        cin>>w;
        cout<<"Enter new string x: ";
        cin>>x;

        int i=0,j=0;

        while(s[i]!='\0'){
            int k=0;

            while(w[k]!='\0' && s[i+k]==w[k]){
                k++;
            }

            if(w[k]=='\0'){ // match
                for(int t=0; x[t]!='\0'; t++){
                    result[j++] = x[t];
                }
                i += k;
            }
            else{
                result[j++] = s[i++];
            }
        }

        result[j]='\0';
        strcpy(s,result);

        cout<<"Updated string = "<<s<<endl;
    }

    // 5. Palindrome
    void palindrome(){
        int i=0;
        int j=strlen(s)-1;
        int flag=1;

        while(i<j){
            if(s[i]!=s[j]){
                flag=0;
                break;
            }
            i++;
            j--;
        }

        if(flag) cout<<"Palindrome\n";
        else cout<<"Not Palindrome\n";
    }
};

int main(){
    Str obj;
    int ch;

    obj.input();

    do{
        cout<<"\n1.Frequency\n2.Substring\n3.Remove\n4.Replace\n5.Palindrome\n6.Exit\n";
        cin>>ch;

        if(ch==1) obj.freq();
        else if(ch==2) obj.substr();
        else if(ch==3) obj.removeChar();
        else if(ch==4) obj.replace();
        else if(ch==5) obj.palindrome();

    }while(ch!=6);

    return 0;
}