Basic C Programs

Display the message “Hello World”.

#include <stdio.h>
int main() 
{
 printf("Hello World");
return 0;
}

Display the area of a rectangle.

#include <stdio.h>
int main() 
{

/* display the area of rectangle
Basic Logic: Area R = L*B
*/

float a;
float b;

printf("Enter The Length Of Rectangle:");
scanf("%f",&a);

printf("Enter The Bredth Of Rectangle:");
scanf("%f",&b);

float area = a*b;
printf("%.2f",area);

return 0;
}

Find the Area and Circumference of a Circle (c=2πr).

#include <stdio.h>
int main() 
{

/* Area and Circumference of a Circle 
Basic Logic: Area R = pi*r*r   c= 2pir
*/

float circumference, area, r;
float pi = 3.14;

printf("Enter The Radius of Circle:");
scanf("%f",&r);

area= pi * r * r;
printf("Area is: %.2f", area);

circumference = 2 * pi * r;
printf("\ncircumference is : %.2f", circumference);

return 0;
}

Print ASCII Value of the input Character.

#include<stdio.h>
int main()
{
char a;
int b;
printf("Enter The Character ");
scanf("%c",&a);
b=a;
printf("\nOutput Is: %d ",b);
return 0;
}

Calculate a Simple Interest.

#include<stdio.h>
int main()
{
int p;
float r, t;
printf("\nEnter Your Principal Amount: ");
scanf("%d",&p);
printf("\nEnter Your Rate of interest : ");
scanf("%f",&r);
printf("\nEnter Your Time period :");
scanf("%f",&t);

float si = p*t*r/100;
printf("Simple intrest is : %f",si);

return 0;
}

Calculate the tax amount an employee must pay. (tax = 15% of income).

#include<stdio.h>
int main()
{
int tax, salary;
printf("\nEnter Your Salary: Rs ");
scanf("%d",&salary);
printf("\nTax Rate is 15%");

float taxamount = salary*15/100;
printf("\nTax Amount is : Rs %.2f", taxamount);


return 0;
}

Convert currency from Ck to Dollar. (1 dollar = Ck. 135.5)

#include<stdio.h>
int main()
{
float ck,dollar;

printf("\nEnter Your ck: Rs ");
scanf("%f",&npr);
printf("\nRate: 1 dollar = Rs.135.5");

float exchange = ck/135.5;
printf("\nExchanged Dollar : $ %.2f", exchange);


return 0;
}

Convert Temperature from Fahrenheit to Celsius. C = 5/9 (f-32). 

#include<stdio.h>
int main()
{
    //Fahrenheit = ((9/5) * Celsius) + 32; 
float fa, ce;

printf("\nEnter Temperature in Fahrenheit: ");
scanf("%f",&fa);


float convert = (fa - 32) * 5 / 9;
printf("\nTemperature in Celcius is:  %.2f", convert);


return 0;
}

Display the Size of the Different Datatypes in C.

#include <stdio.h>

int main() {
  printf("Size of Int Data Types in C = %2d bytes \n", sizeof(short int));
  printf("Size of Long Int Data Types in C = %2d bytes \n", sizeof(long int));
  printf("Size of Float Data Types in C = %2d bytes \n", sizeof(float));
  printf("Size of Double Data Types in C = %2d bytes \n", sizeof(double));
  printf("Size of Long Double Data Types in C = %2d bytes \n", sizeof(long double));
  printf("Size of Char Data Types in C = %2d bytes \n", sizeof(char));
  return 0;
}

Read Integer N and Print the First Three Powers (N^1, N^2, N^3).


#include <stdio.h>

int main() {

    int ck;
    
    printf("Enter Your Number :");
    scanf("%d",&ck);
    
    printf("\nPower 1 : %d", ck);
    printf("\nPower 2 : %d", ck*ck);
    printf("\nPower 3 : %d", ck*ck*ck);

    return 0;
}

Find the square root of an input number.


#include <stdio.h>

int main() {

    int ck;
    printf("Enter Your Number :");
    scanf("%d",&ck);
    
    printf("\nSquare of The Number : %d", ck*ck);
  
    return 0;
}

WAP to find the roots of a quadratic equation of the form ax2+bx+c=0.

xx

WAP to check whether the input number is even or not..


#include <stdio.h>

int main() {

    int ck;
    printf("Enter Your Number :");
    scanf("%d",&ck);
    
 if (ck % 2 == 0) {
        printf("%d is even.\n", ck);
    } else {
        printf("%d is odd.\n", ck);
    }
  
    return 0;
}

WAP to input age and display whether the person is eligible for voting or not.


#include <stdio.h>

int main() {

    int ck;
    printf("Enter Your Age :");
    scanf("%d",&ck);
    
 if (ck <18 ) {
        printf("Your Age is %d so you are not eligible for voting.\n", ck);
    } else {
        printf("Your Age is %d so you are eligible for voting.\n", ck);
    }
  
    return 0;
}

WAP to Find the smallest of two numbers.


#include <stdio.h>

int main() {

    int ck1, ck2;
    printf("Enter 1st Number :");
    scanf("%d",&ck1);
    
        printf("Enter 2nd Number :");
    scanf("%d",&ck2);
    
 if (ck1 <ck2 ) {
        printf("Smallest Number is :%d \n", ck1);
    } else if (ck2 <ck1) {
        printf("Smallest Number is :%d \n", ck2);
    } else {
        printf("Both numbers are equal.\n");
    }
  
    return 0;
}

WAP to Find the greatest of three numbers.


#include <stdio.h>

int main() {

    float ck1, ck2,ck3;
    
    
     printf("Enter 1st Number: ");
    scanf("%f", &ck1);
    
    printf("Enter 2nd Number: ");
    scanf("%f", &ck2);
    
    printf("Enter 3rd Number: ");
    scanf("%f", &ck3);
    
    if (ck1 >= ck2 && ck1 >= ck3) {
        printf("%.2f is the greatest.\n", ck1);
    } else if (ck2 >= ck1 && ck2 >= ck3) {
        printf("%.2f is the greatest.\n", ck2);
    } else {
        printf("%.2f is the greatest.\n", ck3);
    }
  
    return 0;
}

WAP to Check whether the input character Is Uppercase, Lowercase Alphabet or a Digit or a Special Symbol.

#include <stdio.h>

int main() {
    char ch;

    printf("Enter a character: ");
    scanf("%c", &ch);

    if ((ch >= 'A' && ch <= 'Z')) {
        printf("%c is an uppercase letter.\n", ch);
    } else if (ch >= 'a' && ch <= 'z') {
        printf("%c is a lowercase letter.\n", ch);
    } else if (ch >= '0' && ch <= '9') {
        printf("%c is a digit.\n", ch);
    } else {
        printf("%c is a special symbol.\n", ch);
    }

    return 0;
}

Program to Check whether the current year is leap year or not.

#include <stdio.h>

int main() {
    int year;

    printf("Enter a year: ");
    scanf("%d", &year);

    if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
        printf("%d is a leap year.\n", year);
    } else {
        printf("%d is not a leap year.\n", year);
    }

    return 0;
}

WAP to check whether the input character is vowel or consonant. 

#include <stdio.h>

int main() {
    char ck;
    
    printf("Enter Your Character: ");
    scanf("%c", &ck);

    if (ck == 'a' || ck == 'e' || ck == 'i' || ck == 'o' || ck == 'u' ||
        ck == 'A' || ck == 'E' || ck == 'I' || ck == 'O' || ck == 'U') {
        printf("%c is a Vowel Letter\n", ck);
    } else {
        printf("%c is a Consonant\n", ck);
    }
  
    return 0;
}

Write a C program to determine the grade of a student based on their marks using if-else statements.

#include <stdio.h>

int main() {
    int dl, cfa, eng, math, st;
    float per;

    printf("Enter Marks Obtained in DL: ");
    scanf("%d", &dl);
    printf("Enter Marks Obtained in cfa: ");
    scanf("%d", &cfa);
    printf("Enter Marks Obtained in eng: ");
    scanf("%d", &eng);
    printf("Enter Marks Obtained in math: ");
    scanf("%d", &math);
    printf("Enter Marks Obtained in st: ");
    scanf("%d", &st);

    per = (dl + cfa + eng + math + st) / 5.0;
    printf("Percentage = %.2f\n", per);


    if (per >= 90) {
        printf("Grade A+\n");
    } else if (per >= 80) {
        printf("Grade A\n");
    } else if (per >= 70) {
        printf("Grade B+\n");
    } else if (per >= 60) {
        printf("Grade B\n");
    } else if (per >= 50) {
        printf("Grade C+\n");
    } else if (per >= 40) {
        printf("Grade C\n");
    } else {
        printf("Grade F\n");
    }

    return 0;
}

Write a C program to check whether a given number is positive, negative, or zero using if-else statements.

#include <stdio.h>

int main() {
    int ck;

    printf("Enter your number: ");
    scanf("%d", &ck);

    if (ck > 0) {
        printf("The number is positive.\n");
    } else if (ck < 0) {
        printf("The number is negative.\n");
    } else {
        printf("The number is zero.\n");
    }

    return 0;
}

Write a C program to calculate the income tax based on the given salary using if-else statements and tax brackets.

xx

WAP to print multiplication table of a number using for loop

#include <stdio.h>

int main() {
    int ck;

    printf("Enter a number: ");
    scanf("%d", &ck);

    printf("Multiplication Table of %d:\n", ck);
    
    for (int i = 1; i <= 10; ++i) {
        printf("%d x %d = %d\n", ck, i, ck * i);
    }

    return 0;
}

WAP to find the sum of first 100 natural numbers.

#include <stdio.h>

int main() {
    int n = 100; 
    int sum = 0;

    for (int i = 1; i <= n; ++i) {
        sum += i;
    }

    printf("The sum of the first %d natural numbers is: %d\n", n, sum);

    return 0;
}

WAP to input a number and display the sum of all the digits.

#include <stdio.h>

int main() {
    int nbr,nbr1, sum = 0;

    printf("Enter a number: ");
    scanf("%d", &nbr);

    nbr1 = nbr;

    while (nbr > 0) {
        int digit = nbr % 10;
        sum += digit;
        nbr /= 10;
    }

    printf("The sum of digits of %d is: %d\n", nbr1, sum);

    return 0;
}

WAP to reverse a Given Number Using looping.

#include <stdio.h>

int main() {
    int nbr, rnbr = 0;

    printf("Enter a number: ");
    scanf("%d", &nbr);

    int onbr = nbr;

    while (nbr > 0) {
        int digit = nbr % 10;
        rnbr = rnbr * 10 + digit;
        nbr /= 10;
    }

    printf("The reversed number of %d is: %d\n", onbr, rnbr);

    return 0;
}

Number Is a Palindrome or Not.

#include <stdio.h>

int main() {
    int nbr, rnbr = 0, onbr;
    
    printf("Enter a number: ");
    scanf("%d", &nbr);
    
    onbr = nbr;

    while (nbr > 0) {
        int digit = nbr % 10;
        rnbr = rnbr * 10 + digit;
        nbr /= 10;
    }

    if (onbr == rnbr) {
        printf("%d is a palindrome.\n", onbr);
    } else {
        printf("%d is not a palindrome.\n", onbr);
    }

    return 0;
}

Find the Number Is Armstrong or Not Using While Loop.

#include <stdio.h>
#include <math.h>

int main() {
    int number, originalNumber, remainder, n = 0;
    double result = 0.0;

    printf("Enter an integer: ");
    scanf("%d", &number);

    originalNumber = number;

    // Count the number of digits
    while (originalNumber != 0) {
        originalNumber /= 10;
        ++n;
    }

    originalNumber = number;

    // Calculate Armstrong number
    while (originalNumber != 0) {
        remainder = originalNumber % 10;
        result += pow(remainder, n);
        originalNumber /= 10;
    }

    if ((int)result == number) {
        printf("%d is an Armstrong number.\n", number);
    } else {
        printf("%d is not an Armstrong number.\n", number);
    }

    return 0;
}

Display Fibonacci Series.

#include <stdio.h>

int main() {
    int n, first = 0, second = 1, next;

    printf("Enter the number of terms: ");
    scanf("%d", &n);

    printf("Fibonacci Series:\n");

    for (int i = 0; i < n; ++i) {
        if (i <= 1) {
            next = i;
        } else {
            next = first + second;
            first = second;
            second = next;
        }
        printf("%d ", next);
    }

    return 0;
}

Find GCD(HCF) of Two Numbers.

#include <stdio.h>

int gcd(int a, int b) {
    if (b == 0) {
        return a;
    }
    return gcd(b, a % b);
}

int main() {
    int num1, num2;

    printf("Enter 1st number: ");
    scanf("%d", &num1);
    
        printf("\nEnter 2nd number: ");
    scanf("%d", &num2);

    if (num1 < num2) {
        int temp = num1;
        num1 = num2;
        num2 = temp;
    }

    int result = gcd(num1, num2);
    printf("GCD of %d and %d is: %d\n", num1, num2, result);

    return 0;
}

Find LCM of Two Numbers.

#include <stdio.h>

int gcd(int a, int b) {
    if (b == 0) {
        return a;
    }
    return gcd(b, a % b);
}

int main() {
    int num1, num2, lcm;

    printf("Enter 1st number: ");
    scanf("%d", &num1);
    
    printf("Enter 2nd number: ");
    scanf("%d", &num2);

    lcm = (num1 * num2) / gcd(num1, num2);

    printf("LCM of %d and %d is: %d\n", num1, num2, lcm);

    return 0;
}

Count Number of Digits of an Integer Using Loop.

#include <stdio.h>

int main() {
    int number, count = 0;

    printf("Enter an integer: ");
    scanf("%d", &number);

    int temp = number;
    while (temp != 0) {
        temp /= 10;
        count++;
    }

    printf("Number of digits in %d is: %d\n", number, count);

    return 0;
}

WAP to swap the value of two variables by using third variable (temp).

#include <stdio.h>

int main() {
    int a, b;

    printf("Enter 1st Variable, ie a = ");
    scanf("%d", &a);
    
    printf("\nEnter 2nd Variable, ie b = ");
    scanf("%d", &b);

    // Swapping without using a third variable
    a = a + b;
    b = a - b;
    a = a - b;

    printf("After swapping:\n");
    printf("a = %d\n", a);
    printf("b = %d\n", b);

    return 0;
}

WAP to swap the value of two variables without using third variable.

xx

WAP to input any five integers in an array and display the largest one.

#include <stdio.h>

int main() {
    int numbers[5];
    
    printf("Enter five integers:\n");
    for (int i = 0; i < 5; ++i) {
        scanf("%d", &numbers[i]);
    }

    int largest = numbers[0];
    for (int i = 1; i < 5; ++i) {
        if (numbers[i] > largest) {
            largest = numbers[i];
        }
    }

    printf("The largest integer is: %d\n", largest);

    return 0;
}

WAP to input any five integers in an array and display the second largest number.

#include <stdio.h>

int main() {
    int numbers[5];

    printf("Enter five integers:\n");
    for (int i = 0; i < 5; ++i) {
        scanf("%d", &numbers[i]);
    }
    int largest = numbers[0];
    int secondLargest = numbers[0];

    for (int i = 1; i < 5; ++i) {
        if (numbers[i] > largest) {
            secondLargest = largest;
            largest = numbers[i];
        } else if (numbers[i] > secondLargest && numbers[i] != largest) {
            secondLargest = numbers[i];
        }
    }

    printf("The second largest integer is: %d\n", secondLargest);

    return 0;
}

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