Error searching row inside matrix

Question

The exercise asks me to create matrices to store aircraft registration with some variables, done this, the program asks me to search all the information by entering the code. The problem is that when I search for the flight inside menu 3, the program stops.

main(){


    int menu;
    string codigo, nome, qtpol, ori, dest;
    int qtcad = 0, linha;
    string mat[1][5];

cout<<"Cadastro de Avioes";

    cout<<"1 - Menu Principal\n";
    cout<<"2 - Cadastrar Avioes\n";
    cout<<"3 - Pesquisar Voos\n";
    cout<<"4 - Sair\n";
    cin>>menu;
    while(menu!=4){

        if(menu==1){
    cout<<"Cadastro de Avioes";

    cout<<"1 - Menu Principal\n";
    cout<<"2 - Cadastrar Avioes\n";
    cout<<"3 - Pesquisar Voos\n";
    cout<<"4 - Sair\n";
    cin>>menu;
        }

    else if(menu==2){

        cout<<"Quantos Cadastros Deseja Fazer:";
         cin>>qtcad;
         string mat[qtcad][5];  
    for(int l=0;l<qtcad;l++){
        cout<<"Digite o Codigo do Voo:";
        cin>>mat[l][0];
        cout<<"Digite o Nome da CIA:";
        cin>>mat[l][1];
        cout<<"Digite a Quantidade de Poltronas:";
        cin>>mat[l][2];
        cout<<"Informe a Origem:";
        cin>>mat[l][3];
        cout<<"Informe o Destino:";
        cin>>mat[l][4];     
                        }
        cout<<"Cadastro Realizado com Sucesso.";
        Sleep(2000);
        system("cls");
        menu=1;
    }

    else if(menu==3){
    cout<<"Digite um Codigo para pesquisar um voo:";    
    cin>>codigo;
    cout<<qtcad;

    for(int l=0;l<qtcad;l++){
        for(int c=0;c<5;c++){

        if(codigo==mat[l][c]){
            linha=l;
            }
        }   
    }

    for(int c=0;c<5;c++){
        cout<<mat[linha][c];
                        }

    }
    else{
        cout<<"erro";
    }
}

return 0;

}

Answer 1

As there are many mistakes I will list them instead of trying to fix a specific point.

• Indenting and naming variables that have meaning is no joke, it helps the most advanced programmers to understand what they are doing and find possible problems, imagine for those who are starting. Nobody should program without having this very clear and do in all the codes, even the simplest ones that exist. It costs nothing to do it the right way and so you train your brain to do it better and better. If you do it anyway you train your brain to do bad.
• I have already said in the comments that I do not agree with the idea of mixing C with C++, I should choose a language and follow it. If you’re gonna do it in C, you can’t use it cin, cout, string, Sleep(), etc. If you are going to do it in C++, you should use vector or at least array that are structures ready better than the array C that is even a array for real.
• In any case should not have one array two-dimensional there, this is wrong concept. Even if it works it is not right and then you will learn to do wrong. You should create a struct or even a class in C++, but I’ll stick with C and avoid talking in resources like this. Then you would have only one array of these structures. Maybe you haven’t learned this yet, but then you shouldn’t be trying to solve this kind of problem. First learn all the necessary mechanisms for the problem. If there is a teacher demanding something without having passed the appropriate mechanisms I can only regret and indicate to see with him if he can not follow the class otherwise, is hurting you.
• Try to declare the variables closest to where it is used, don’t declare everything before, this is an old way of doing that decreases readability.
• Note that the menu is repeated, simply initialize the variable with the appropriate value and do not need to create it before the loop.
• The ideal is that each option was made in a function. You may not have learned this yet, but again this is too complex a problem for those who do not know how to work with functions.
• Even if you do so the selection would be better with switch, If you made a mistake with him, you should try to figure out what it is and fix it, not throw it all away and do it another way. You need to understand what you’re doing. The goal of learning programming is not to make it work, it’s to make it right, it’s to understand what you’re doing and what’s happening.
• There shouldn’t be an option for the main menu, or there shouldn’t be an option to quit, only an output option is useful and an option that does something that would happen anyway doesn’t have to exist.
• Has variable that is declared twice, this should not even compile.
• There’s no reason to have a nested loop to research, actually with the use of struct the error becomes more obvious and would not even happen.
• Ask for the size of array does not make sense, this is information you have and should not expose to the user, this is detail of your code, maybe the error is there.
• I’d have to clean this up first to make it easier to see the error. You can try to find it that way, but it takes a lot of work on something that shouldn’t be this way.
• There are other little details I don’t even think are important right now.