Calculator

#include <stdio.h>
#include <stdlib.h>

float pot (float a, float b)
{
    int i = 0;
    float pow = a;

    for (i = 1; i < (int) b; i++)
        pow = pow * a;
    return pow;
}

#include <iostream>
#include <stdio.h>

using namespace std;

int main()
{
    float n1 = 0, n2 = 0, r = 0;
    char c;
    int ctr = 0;

    printf("Simple calculator by andreafiori\n");

    do
    {
        cin >> n1;
        cin >> c;
        cin >> n2;

        switch (c)
        {
            case '+' :
                r = n1 + n2;
                break;
            case '-' :
                r = n1 - n2;
                break;
            case '*' :
                r = n1 * n2;
                break;
            case '^' :
                r = pot (n1, n2);
                break;
            case '/' :
                if (n2 == 0)
                    printf("The value is not valid!\n");
                else
                    r = n1 / n2;
                break;
            default :
                printf("The operation is not allowed!\n");
                break;
        }

        printf (" = %f\nRepeat ? [1 = yes/ 0 = no] ", r);
        scanf ("%d", &ctr);
        } while (ctr == 1);

        return 0;
}