4. Programming Projects

1. #include <stdio.h>

int main(void)

{

    int number;

    printf("Enter a two-digit number: ");

    scanf("%2d", &number);

    int num1 = (number / 10);

    int num2 = (number % 10);

    printf("The reversal is : %1d%1d\n", num2, num1);

    return 0;

}

2. #include <stdio.h>

int main(void)

{

    int number;

    printf("Enter a three-digit number: ");

    scanf("%3d", &number);

    int num1 = (number / 100);

    int num2 = ( (number / 10) - ( num1 * 10) );

    int num3 = (number % 10);

    printf("The reversal is : %1d%1d%1d\n", num3, num2, num1);

    return 0;

}

3. #include <stdio.h>

int main(void)

{

    int num1, num2, num3;

    printf("Enter a three-digit number: ");

    scanf("%1d%1d%1d", &num1, &num2, &num3);

    printf("The reversal is : %1d%1d%1d\n", num3, num2, num1);

    return 0;

}

4. #include <stdio.h>

int main(void)

{

    int number;

    printf("Enter a number between 0 and 32767 : ");

    scanf("%d",&number);

    int n5 = number % 8;

    number /= 8;

    int n4 = number % 8;

    number /= 8;

    int n3 = number % 8;

    number /= 8;

    int n2 = number % 8;

    number /= 8;

    int n1 = number % 8;

    number /= 8;

    printf("In octal, your number is %1d%1d%1d%1d%1d\n", n1, n2, n3, n4, n5);

    return 0;

}

5. #include <stdio.h>

int main(void)

{

    int d, i1, i2, i3, i4, i5, j1, j2, j3, j4, j5, 

        first_sum, second_sum, total;

    

    printf("Enter eleven digits : ");

    scanf("%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d",

         &d, &i1, &i2, &i3, &i4, &i5, &j1, &j2, &j3, &j4, &j5);

    first_sum = d + i2 + i4 + j1 + j3 + j5;

    second_sum = i1 + i3 + i5 + j2 + j4;

    total = 3 * first_sum + second_sum;

    printf("Check digit : %d\n", 9 - ( (total - 1) % 10) );

    return 0;

}

6. #include <stdio.h>

int main(void)

{

    int d, i1, i2, i3, i4, i5, j1, j2, j3, j4, j5, j6, 

        first_sum, second_sum, total;

    

    printf("Enter the first 12 digits of an EAN : ");

    scanf("%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d%1d",

         &d, &i1, &i2, &i3, &i4, &i5, &j1, &j2, &j3, &j4, &j5, &j6);

    first_sum = i1 + i3 + i5 + j2 + j4 + j6;

    second_sum = d + i2 + i4 + j1 + j3 + j5;

    total = ( (3 * first_sum) + second_sum );

    printf("Check digit : %d\n", 9 - ( (total - 1) % 10) );

    return 0;

}