C Programms: August 2014

Monday, August 4, 2014

C Program to Convert a Decimal Number to Binary & Count the Number of 1s

This C Program converts a decimal number into binary & count the number of 1s. The program uses module operation and multiplication with base 2 operation for conversion. It also uses modulo operation to check for 1′s and accordingly increments the count of 1s.

Here is source code of the C program to convert a decimal number to binary & count the number of 1s. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to accept a decimal number and convert it to binary

 * and count the number of 1's in the binary number

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```

    long num, decimal_num, remainder, base = 1, binary = 0, no_of_1s = 0;

```
 
```

    printf("Enter a decimal integer \n");

```
    scanf("%ld", &num);
```
```
    decimal_num = num;
```
```
    while (num > 0)
```
```
    {
```
```
        remainder = num % 2;
```
```
        /*  To count no.of 1s */
```
```
        if (remainder == 1)
```
```
        {
```
```
            no_of_1s++;
```
```
        }
```

        binary = binary + remainder * base;

```
        num = num / 2;
```
```
        base = base * 10;
```
```
    }
```

    printf("Input number is = %d\n", decimal_num);

    printf("Its binary equivalent is = %ld\n", binary);

    printf("No.of 1's in the binary number is = %d\n", no_of_1s);

```
}
```

$ cc pgm46.c
$ a.out
Enter a decimal integer
134
Input number is = 134
Its binary equivalent is = 10000110
No.of 1's in the binary number is = 3

C Program to Illustrate how User Authentication is Done

This C Program illustrate how user authentication is done. The program accepts the username and password. It checks whether the password is correct with respect to the username.

Here is source code of the C program to illustrate user authentication. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program is to illustrate how user authentication is done.

 * Program asks for the user name and password and displays

```
 * the password as '*' character
```
```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```
```
 char password[10], username[10], ch;
```
```
 int i;
```
```
 
```
```
 printf("Enter User name: ");
```
```
 gets(username);
```

 printf("Enter the password < any 8 characters>: ");

```
 for (i = 0; i < 8; i++)
```
```
 {
```
```
            ch = getchar();
```
```
            password[i] = ch;
```
```
            ch = '*' ;
```
```
            printf("%c", ch);
```
```
 }
```
```
        password[i] = '\0';
```

 /*  Original password can be printed, if needed */

```
 printf("\n Your password is :");
```
```
 for (i = 0; i < 8; i++)
```
```
 {
```
```
            printf("%c", password[i]);
```
```
 }
```
```
}
```

$ cc pgm43.c
$ a.out
Enter User name: rajaraman
Enter the password <any 8 characters>: shashi12
********
Your password is :shashi12

C Program to Reverse a Given Number

This C Program reverses a given number by using modulo operation.

Here is source code of the C program to reverse a given number. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to accept an integer and reverse it

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```

    long  num, reverse = 0, temp, remainder;

```
 
```
```
    printf("Enter the number\n");
```
```
    scanf("%ld", &num);
```
```
    temp = num;
```
```
    while (num > 0)
```
```
    {
```
```
        remainder = num % 10;
```

        reverse = reverse * 10 + remainder;

```
        num /= 10;
```
```
    }
```

    printf("Given number = %ld\n", temp);

    printf("Its reverse is = %ld\n", reverse);

```
}
```

$ cc pgm42.c
$ a.out
Enter the number
567865
Given number   = 567865
Its reverse is = 568765

C Program to Convert the given Binary Number into Decimal

This C Program converts the given binary number into decimal. The program reads the binary number, does a modulo operation to get the remainder, multiples the total by base 2 and adds the modulo and repeats the steps.

Here is source code of the C program to covert binary number to decimal. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to convert the given binary number into decimal

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```

    int  num, binary_val, decimal_val = 0, base = 1, rem;

```
 
```

    printf("Enter a binary number(1s and 0s) \n");

    scanf("%d", &num); /* maximum five digits */

```
    binary_val = num;
```
```
    while (num > 0)
```
```
    {
```
```
        rem = num % 10;
```

        decimal_val = decimal_val + rem * base;

```
        num = num / 10 ;
```
```
        base = base * 2;
```
```
    }
```

    printf("The Binary number is = %d \n", binary_val);

    printf("Its decimal equivalent is = %d \n", decimal_val);

```
}
```

$ cc pgm38.c
$ a.out
Enter a binary number(1s and 0s)
10101001
The Binary number is = 10101001
Its decimal equivalent is = 169S

C Program to Read Two Integers M and N & Swap their Values

This C Program reads two integers & swap their values.

Here is source code of the C program to read two integers & swap their values. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to read two integers M and N and to swap their values.

 * Use a user-defined function for swapping. Output the values of M

```
 * and N before and after swapping.
```
```
 */
```
```
#include <stdio.h>
```
```
void swap(float *ptr1, float  *ptr2);
```
```
 
```
```
void main()
```
```
{
```
```
    float m, n;
```
```
 
```

    printf("Enter the values of M and N \n");

```
    scanf("%f %f", &m, &n);
```

    printf("Before Swapping:M = %5.2ftN = %5.2f\n", m, n);

```
    swap(&m, &n);
```

    printf("After Swapping:M  = %5.2ftN = %5.2f\n", m, n);

```
}
```

/*  Function swap - to interchanges the contents of two items */

```
void swap(float *ptr1, float *ptr2)
```
```
{
```
```
    float temp;
```
```
 
```
```
    temp = *ptr1;
```
```
    *ptr1 = *ptr2;
```
```
    *ptr2 = temp;
```
```
}
```

$ cc pgm36.c
$ a.out
Enter the values of M and N
2 3
Before Swapping:M =  2.00    N =  3.00
After Swapping:M  =  3.00    N =  2.00

C Program to Find the Number of Integers Divisible by 5

This C Program calculates the number of integers divisible by 5. This program checks if the given number is divisible by 5 and then prints an appropriate message.

Here is source code of the C program to calculate the number of integers divisible by 5. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to find the number of integers divisible by

 * 5 between the given range num1 and num2, where num1 < num2.

```
 *
```

 * Also find the sum of all these integer numbers which are divisible

```
 * by 5 and display the total.
```
```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```

    int i, num1, num2, count = 0, sum = 0;

```
 
```

    printf("Enter the value of num1 and num2 \n");

```
    scanf("%d %d", &num1, &num2);
```

    /* Count the number and compute their sum*/

    printf("Integers divisible by 5 are \n");

```
    for (i = num1; i < num2; i++)
```
```
    {
```
```
        if (i % 5 == 0)
```
```
        {
```
```
            printf("%3d,", i);
```
```
            count++;
```
```
            sum = sum + i;
```
```
        }
```
```
    }
```

    printf("\n Number of integers divisible by 5 between %d and %d =

```
 %d\n", num1, num2, count);
```

    printf("Sum of all integers that are divisible by 5 = %d\n", sum);

```
}
```

$ cc pgm18.c
$ a.out
Enter the value of num1 and num2
12 17
Integers divisible by 5 are
 15,
Number of integers divisible by 5 between 12 and 17 = 1
Sum of all integers that are divisible by 5 = 15

C Program to Reverse a Number & Check if it is a Palindrome

This C Program reverses a number & checks if it is a palindrome or not. First it reverses a number. Then it checks if given number and reversed numbers are equal. If they are equal, then its a palindrome. Here is source code of the C program to reverse a number & checks it is a palindrome or not. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to reverse a given integer number and check

 * whether it is a palindrome. Display the given number

```
 * with appropriate message
```
```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```

    int num, temp, remainder, reverse = 0;

```
 
```
```
    printf("Enter an integer \n");
```
```
    scanf("%d", &num);
```

    /*  original number is stored at temp */

```
    temp = num;
```
```
    while (num > 0)
```
```
    {
```
```
        remainder = num % 10;
```

        reverse = reverse * 10 + remainder;

```
        num /= 10;
```
```
    }
```

    printf("Given number is = %d\n", temp);

    printf("Its reverse is  = %d\n", reverse);

```
    if (temp == reverse)
```

        printf("Number is a palindrome \n");

```
    else
```

        printf("Number is not a palindrome \n");

```
}
```

$ cc pgm13.c
$ a.out
Enter an integer
6789
Given number is = 6789
Its reverse is  = 9876
Number is not a palindrome
 
$ a.out
Enter an integer
58085
Given number is = 58085
Its reverse is  = 58085
Number i

C Program to Calculate the Sum of Odd & Even Numbers

This C Program calculates the sum of odd & even numbers. The program first seperates odd and even numbers. Later it adds the odd and even numbers seperately.

Here is source code of the C program to calculate the sum of odd & even numbers. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to find the sum of odd and even numbers from 1 to N

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```

    int i, num, odd_sum = 0, even_sum = 0;

```
 
```
```
    printf("Enter the value of num\n");
```
```
    scanf("%d", &num);
```
```
    for (i = 1; i <= num; i++)
```
```
    {
```
```
        if (i % 2 == 0)
```
```
            even_sum = even_sum + i;
```
```
        else
```
```
            odd_sum = odd_sum + i;
```
```
    }
```

    printf("Sum of all odd numbers  = %d\n", odd_sum);

    printf("Sum of all even numbers = %d\n", even_sum);

```
}
```

$ cc pgm12.c
$ a.out
Enter the value of num
10
Sum of all odd numbers  = 25
Sum of all even numbers = 30
 
$ a.out
Enter the value of num
100
Sum of all odd numbers  = 2500
Sum of all even numbers = 2550

C Program to Find the Biggest of 3 Numbers

This C Program calculates the biggest of 3 numbers.The program assumes 3 numbers as a, b, c. First it compares any 2 numbers check which is bigger. After that it compares the biggest element with the remaining number. Now the number which is greater becomes your biggest of 3 numbers. Here is source code of the C program to calculate the biggest of 3 numbers. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to find the biggest of three numbers

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```
```
    int num1, num2, num3;
```
```
 
```

    printf("Enter the values of num1, num2 and num3\n");

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

    printf("num1 = %d\tnum2 = %d\tnum3 = %d\n", num1, num2, num3);

```
    if (num1 > num2)
```
```
    {
```
```
        if (num1 > num3)
```
```
        {
```

            printf("num1 is the greatest among three \n");

```
        }
```
```
        else
```
```
        {
```

            printf("num3 is the greatest among three \n");

```
        }
```
```
    }
```
```
    else if (num2 > num3)
```

        printf("num2 is the greatest among three \n");

```
    else
```

        printf("num3 is the greatest among three \n");

```
}
```

$ cc pgm6.c
$ a.out
Enter the values of num1, num2 and num3
6 8 10
num1 = 6  num2 = 8  num3 = 10
num3 is the greatest among three

C Program to Check if a given Integer is Positive or Negative

his C Program checks if a given integer is positive or negative. Here if a number is greater than 0 then that number is a positive number. If a number is less than 0 then the number is negative number.

Here is source code of the C program which checks a given integer is positive or negative. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to check whether a given integer is positive

```
 * or negative
```
```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```
```
    int number;
```
```
 
```
```
    printf("Enter a number \n");
```
```
    scanf("%d", &number);
```
```
    if (number >= 0)
```

        printf("%d is a positive number \n", number);

```
    else
```

        printf("%d is a negative number \n", number);

```
}
```

$ cc pgm5.c
$ a.out
Enter a number
-10
-10 is a negative number
 
$ a.out
Enter a number
45
45 is a positive number

C Program to Check if a given Integer is Odd or Even

This C Program checks if a given integer is odd or even. Here if a given number is divisible by 2 with the remainder 0 then the number is even number. If the number is not divisible by 2 then that number will be odd number.

Here is source code of the C program which checks a given integer is odd or even. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program to check whether a given integer is odd or even

```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```
```
    int ival, remainder;
```
```
 
```
```
    printf("Enter an integer : ");
```
```
    scanf("%d", &ival);
```
```
    remainder = ival % 2;
```
```
    if (remainder == 0)
```

        printf("%d is an even integer\n", ival);

```
    else
```

        printf("%d is an odd integer\n", ival);

```
}
```

$ cc pgm4.c
$ a.out
Enter an integer : 100
100 is an even integer
 
$ a.out
Enter an integer : 105
105 is an odd integer