c++ - Should I use goto statement here? -

a fine gentleman told me goto statements bad, don't see how can not use here:

int main() {       using namespace std;    int x;    int y;    int z;    int a;    int b;    calc: //how can here, without using goto?    {    cout << "to begin, type number" << endl;    cin >> x;    cout << "excellent!" << endl;    cout << "now need type second number" << endl;    cin >> y;    cout << "excellent!" << endl;    cout << "now, want these numbers?" << endl;    cout << "alt. 1 +" << endl;    cout << "alt. 2 -" << endl;    cout << "alt. 3 *" << endl;    cout << "alt. 4 /" << endl;    cin >> a;         if (a == 1) {     z = add(x, y);    }     if (a == 2) {     z = sub(x, y);    }     if (a == 3) {     z = mul(x, y);    }         if (a == 4) {     z = dis(x, y);    } }  cout << "the answer math question "; cout << z << endl; cout << "do want enter question?" << endl; cout << "type 1 yes" << endl; cout << "type 0 no" << endl; cin >> b;      if (b == 1) {     goto calc; } cout << "happy trails!" << endl; return 0; } 

it calculator, can see. also, if want, can suggest better way (if exists) let user choose operation (+ - * /). header files under control. apologize lot of cout statements.

here cleaned-up , formatted version using do/while loop structure:

using namespace std;  int main() {        int x, y, z, a, b;      {         cout << "to begin, type number" << endl;         cin >> x;         cout << "excellent!" << endl;         cout << "now need type second number" << endl;         cin >> y;         cout << "excellent!" << endl;         cout << "now, want these numbers?" << endl;         cout << "alt. 1 +" << endl;         cout << "alt. 2 -" << endl;         cout << "alt. 3 *" << endl;         cout << "alt. 4 /" << endl;         cin >> a;         if (a == 1) {             z = add(x, y);         }         else if (a == 2) {             z = sub(x, y);         }         else if (a == 3) {             z = mul(x, y);         }         else if (a == 4) {             z = dis(x, y);         }         cout << "the answer math question ";         cout << z << endl;         cout << "do want enter question?" << endl;         cout << "type 1 yes" << endl;         cout << "type 0 no" << endl;         cin >> b;     } while (b != 0);     cout << "happy trails!" << endl;     return 0; }