How do you compare parts of a string with another string?

[Sebhar2002]

I've just begun programmimg and I am trying to do a Morse encrypting program but I don't know how to compare part of a string with another one(in this case a letter) if I dont, the programm just jumps all the code

  #include <iostream>
#include <string>

using namespace std;

int main()
{
    int count = 0, length;
    string input;
    cout << "changes text to morse and morse to text; \n";
    cout << "Between letters: |; Between words: ~~ \n";
    getline (cin, input);
    length = (int)input.length();
    for (count = 0; count < length; count++)
    {
        input[count] = tolower(input[count]);
        //Letters
       if (input == "a") {cout << ".-"; cout << "|";}
       if (input == "b") {cout << "-..."; cout << "|";}
       if (input == "c") {cout << "-.-."; cout << "|";}
       if (input == "d") {cout << "-.."; cout << "|";}
       if (input == "e") {cout << "."; cout << "|";}
       if (input == "f") {cout << "..-."; cout << "|";}
       if (input == "g") {cout << "--."; cout << "|";}
       if (input == "h") {cout << "...."; cout << "|";}
       if (input == "i") {cout << ".."; cout << "|";}
       if (input == "j") {cout << ".---"; cout << "|";}
       if (input == "k") {cout << "-.-"; cout << "|";}
       if (input == "l") {cout << ".-.."; cout << "|";}
       if (input == "m") {cout << "--"; cout << "|";}
       if (input == "n") {cout << "-."; cout << "|";}
       if (input == "o") {cout << "---"; cout << "|";}
       if (input == "p") {cout << ".--."; cout << "|";}
       if (input == "q") {cout << "--.-"; cout << "|";}
       if (input == "r") {cout << ".-."; cout << "|";}
       if (input == "s") {cout << "..."; cout << "|";}
       if (input == "t") {cout << "-"; cout << "|";}
       if (input == "u") {cout << "..-"; cout << "|";}
       if (input == "v") {cout << "...-"; cout << "|";}
       if (input == "w") {cout << ".--"; cout << "|";}
       if (input == "x") {cout << "-..-"; cout << "|";}
       if (input == "y") {cout << "-.--"; cout << "|";}
       if (input == "z") {cout << "--."; cout << "|";}

       //Spaces between letters
       if (input == " ") {cout << "~~"; cout << "|";}

       //Numbers
       if (input == "1") {cout << ".----"; cout << "|";}
       if (input == "2") {cout << "..---"; cout << "|";}
       if (input == "3") {cout << "...--"; cout << "|";}
       if (input == "4") {cout << "....-"; cout << "|";}
       if (input == "5") {cout << "....."; cout << "|";}
       if (input == "6") {cout << "-...."; cout << "|";}
       if (input == "7") {cout << "--..."; cout << "|";}
       if (input == "8") {cout << "---.."; cout << "|";}
       if (input == "9") {cout << "----."; cout << "|";}
       if (input == "0") {cout << "-----"; cout << "|";}
    }
    cout << "Done";
}

[megatron 0]

Try:

if(input[count] == 'a') { ... }
...

[Sebhar2002]

Thanks megatron 0