Not close consol

[porkshop]

How can I make the program run over again without closing the console?
And also, can I make it output "invalid syntax" if it is not an integer?

  #include <iostream>
#include <time.h>
#include <stdlib.h>
using namespace std;

int main() {

	int a, b;
	srand(time(NULL));
	a = rand() % 3 + 1;
	cout << "Int 1-3\n";
	cin >> b;

	if (b == a) cout << "Success!\n";
	else cout << "Failure!\n";

}

[z05DSL3A]

A while or do-while loop.

[porkshop]

Ok thanks bot now I get an error message saying that win and loss are not initialized

#include <iostream>
#include <time.h>
#include <stdlib.h>
using namespace std;

int main() {


	int a, b, c = 1;
	while (c<100) {
		srand(time(NULL));
		a = rand() % 3 + 1;
		cout << "Int 1-3\n";
		cin >> b;
		int win, loss;
		if (b == a) {
			cout << "Success!\n\n";
			win++;
			cout << "RWP = " << win / (win + loss);
		}
		else {
			cout << "Failure!\n\n";
			loss++;
			cout << "RWP = " << win / (win + loss);
		}
		c++;
	}

}

[nuderobmonkey]

#include <iostream>
#include <cstdlib>
#include <ctime>
#include <stdexcept>


// Reading numbers by discarding all mismatching inputs
// is a little bit tricky:
//
int read_int(std::istream & is)
{
    while (true)
    {
        std::string tmp;
        int number;
        while (std::getline(is, tmp))
        {
            try {
                number = std::stoi(tmp);
            }
            catch ( std::invalid_argument & e)
            {
                std::cout << "Invalid syntax.\n";
                continue;
            }
            return number;
        }
        throw std::runtime_error("Couldn't read from istream!\n");
    }
}

int main()
{
    int a, b, win{}, loss{}, c{};   // win,loss, c will initialized to 0
    std::srand(std::time(nullptr));
    while (c++ < 100)
    {
        a = std::rand() % 3 + 1;
        std::cout << "Int 1-3\n";
        b = read_int(std::cin);
        
        if (b == a)
        {
            std::cout << "Success!\n\n";
            ++win;
        }
        else
        {
            ++loss;
            std::cout << "Failure!\n\n";
        }
        std::cout << "RWP = " << double(win) / (win + loss) << '\n';
    }
}

[porkshop]

Now it says that it divides by 0, but there is no such place...

using namespace std;

int main() {


	int a, b, c = 1;
	while (c<100) {
		srand(time(NULL));
		a = rand() % 3 + 1;
		cout << "Int 1-3\n";
		cin >> b;
		int win=1, loss=1;
		float p = win / (win + loss);
		if (b == a) {
			cout << "Success!\n\n";
			win++;
			cout << "RWP = " << p << "\n";
		}
		else {
			cout << "Failure!\n\n";
			loss++;
			cout << "RWP = " << p << "\n";
		}
		c++;
	}

}

[dutch]

In the code you've shown there is no place where it will divide by 0, so you were probably running some other code.

Anyway, you should put srand before the loop (you don't want to seed the RNG every iteration).
And you need to initialize win and loss before the loop, too.
And your calculation with the float needs to be done in floating point, which requires a cast on one of the integer operands.

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

const int NumTries = 100;

int main() {
	srand(time(0));
	int wins = 0;
	for (int tries = 0; tries < NumTries; ++tries) {
		int a = rand() % 3 + 1;
		cout << "Int 1-3\n";
		int b;
		cin >> b;
		if (b == a) {
			cout << "win\n";
			++wins;
		}
		else
			cout << "loss\n";
		cout << "RWP = " << float(wins) / (tries + 1) << '\n';
	}
}

[porkshop]

Ok thanks, but how can I make a statement such as "if a > 0 and b>0 and c>0" in one line of code not three different if statements

[Repeater]

if ( (a > 0) && (b>0) && (c>0) )