exercice1-commenté

/*
**Filename : exercise_1
**
**Made by : LIONTI Theo / DESJARDINS Alexis
**
**Description : Affichage de nombres régulier dans un intervalle [a;b] saisi par l'utilisateur.
**
*/


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

int main()
{
    int a, b, temp, digit1, digit2, digit3, digit4, digit5, digit6, digit7, digit8, i, regulars, y, sum, x, restart, c, w;

   do{

     x=w=0;
    a = b = 129;           //allows the loop to start


    printf("Entrez un interval d'entiers [a,b] avec a > -128 et b < 128\n");

    while(a < -127 || a > 127){
        printf("\na = ");               //forces user to input values between -127 and 127
        scanf("%d", &a);
    }

    while(b < -127 || b > 127 || a > b){
        printf("\nb = ");
        scanf("%d", &b);
    }

    printf("Les nombres reguliers entre %d et %d sont :", a, b);
    regulars = 0;

    for(y=0;y<=1;y++){

        for(i=a;i<=b;i++){    //converts i to binary. Every digit is stocked in a separate variable
            temp = abs(i);


            digit1 = temp % 2;
            temp = temp / 2;

            digit2 = temp % 2;
            temp = temp / 2;

            digit3 = temp % 2;
            temp = temp / 2;

            digit4 = temp % 2;
            temp = temp / 2;

            digit5 = temp % 2;
            temp = temp / 2;

            digit6 = temp % 2;
            temp = temp / 2;

            digit7 = temp % 2;
            temp = temp /2;

            digit8 = 0;





                if(i<0){          // if working on negative values converts the absolute value to negative value by replacing each digit
                    digit8 = 1;

                    if (digit7)
                        digit7 = 0;

                    else
                        digit7 = 1;

                    if(digit6)
                        digit6 = 0;

                    else
                        digit6 = 1;

                    if(digit5)
                        digit5 =0;

                    else
                        digit5 = 1;

                    if (digit4)
                        digit4 = 0;

                    else
                        digit4 = 1;

                    if(digit3)
                        digit3 = 0;

                    else
                        digit3 = 1;


                    if(digit2)
                        digit2 =0;

                    else
                        digit2 = 1;


                    if(digit1)
                        digit1 = 0;

                    else
                        digit1 = 1;




                    if(!digit1){               //then adds 1
                        digit1++;
                                }

                    else {
                        digit1 = 0;

                        if(!digit2){
                            digit2++;
                                    }
                        else {
                            digit2 = 0;


                            if(!digit3){
                                digit3++;
                                        }
                            else {
                                digit3 = 0;
                                if(!digit4){
                                    digit4++;
                                            }
                                else{
                                    digit4 = 0;
                                    if(!digit5){
                                        digit5++;
                                                }
                                    else{
                                        digit5 = 0;
                                        if(!digit6){
                                        digit6++;
                                                    }
                                        else{
                                            digit6 = 0;
                                            if(!digit7){
                                                digit7 = 1;
                                                        }
                                            else{
                                                digit7 = 0;

                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }

                }



sum = digit1+digit2+digit3+digit4+digit5+digit6+digit7+digit8; //if the number is regular, the sum of its digits is 4

    if(sum == 4){
            if(y == 0){

                regulars++;
            }




      if(y==1){
x++;

                 if(x == regulars-1){
                printf(" %d et", i)

                }
                else if(x==regulars){
                    printf(" %d.\n", i);
                    w=1;
                }
                else
                    printf(" %d,", i);

      }
    }

        }


}
if(regulars==0){
                printf(" ERREUR - il n'y a pas d'entiers reguliers entre %d et %d", a, b); //ouptuts
               // return 0;
           }



if(w==1){


                do{
                    while(c != '\n' && c != EOF)    //emptying buffer
    {
        c = getchar();
    }
                        printf("\n\nRelancer ? [Y/N] : ");
                        temp = 0;         //alloxs the user to start again with != values
           scanf("%c", &temp);
           }while(temp != 'y' && temp != 'Y' && temp !='n' && temp != 'N');

           if(temp=='y'||temp=='Y')
           restart = 1;

           if(temp =='n' || temp =='N')
            restart = 0;

        }
    }while(restart);


   return 0;
}