➤ If-else Statement in C
➤ Programs on if-else
➤ Switch Case in C
➤ Switch case Programs
➤ Conditional Operator
➤ While loop in C
➤ Do-while loop in C
➤ While vs do-while
➤ For loop in C
➤ Break keyword in C
➤ Continue keyword in C
➤ Break vs Exit in C
➤ Goto keyword in C
☕️ Flow Control Programs
➤ Largest in 3 Numbers
➤ Find Grade of student
➤ Find the absolute value
➤ Vowel or Consonant
➤ Leap Year Program
➤ Simple calculator in C
➤ Check Odd or Even
➤ Roots of Quadratic Equation
➤ Find Reverse of Number
➤ Factors of a number in C
➤ Generate Multiplication table
➤ Find Power of a Number
➤ Find GCD and LCM
➤ Find factorial of Number
➤ Count Number of Digits
➤ Sum of digits in Number
➤ Sum of N Natural Numbers
➤ Sum of Squares of Natural No.
➤ Find Sum of Odd Numbers
➤ Find the Sum of Series
➤ Find Fibonacci series in C
➤ Sum of the Fibonacci series
➤ Sum until enters +ve numbers
➤ Sum of max 10 no. & Skip -ve
☕️ C Conversion Programs
➤ Celsius to Fahrenheit
➤ Fahrenheit to Celsius
➤ Decimal ↔ Binary
➤ Decimal ↔ Octal
➤ Octal ↔ Binary in C
☕️ Number Programs in C
➤ Prime Number in C
➤ Strong Number in C
➤ Krishnamurthy Number
➤ Neon Number in C
➤ Palindrome number
➤ Perfect Number in C
➤ Armstrong Number
☕️ Pattern Programs in C
➤ Pattern programs in C
➤ Printing pattern using loops
➤ Floyd’s triangle Program
➤ Pascal Triangle Program
➤ Pyramid Star Pattern in C
➤ Diamond Pattern Programs
➤ Half Diamond pattern in C
➤ Print Diamond Pattern
➤ Hollow Diamond Pattern
➤ Diamond Pattern of Numbers
Previously we have written a program to find the sum of N natural numbers in C, now we will write the program for the sum of squares of first N natural numbers in C using while loop, for loop, and without loop.
Prerequisites:-
Sum of squares of first N natural numbers is given as = 12 + 22 + 32 + 42 + ...... + (n-1)2 + n2
To find the sum of the squares of N natural numbers declare a variable and initialize it with value 1. Declare another variable sum and initialize it with 0. Now, in every iteration increase sum value until the value N.
Sum of squares of N natural numbers in C using for loop
#include<stdio.h>
int main()
{
int n, sum=0;
printf("Enter n value: ");
scanf("%d", &n);
for(int i=0; i<=n; i++)
{
sum += (i*i);
}
printf("Sum of squares of first %d natural numbers = %d",
n, sum);
return 0;
}Output for the different test-cases:-
Enter n value: 5
Sum of squares of first 5 natural numbers = 55
Enter n value: 10
Sum of squares of first 10 natural numbers = 385
In this program, the variable n store the value of the number that is entered by the user. Similarly, the variable sum store the result.
The sum of squares of n natural numbers also can be calculated in reverse order from the previous one. For example, the sum of squares of first N natural numbers is given as = n2 + (n-1)2 + … + 32 + 22 + 12
In this case, the loop control variable should initialize with “n” and the decrement operator should be used. Below program shows it,
#include<stdio.h>
int main()
{
int n, sum=0;
printf("Enter n value: ");
scanf("%d", &n);
for(int i=n; i>=0; i--)
{
sum += i*i;
}
printf("Sum of squares of first %d natural numbers = %d",
n, sum);
return 0;
}Using while loop
#include<stdio.h>
int main()
{
int n, sum=0, i=0;
printf("Enter n value: ");
scanf("%d", &n);
while(i<=n)
{
sum += (i*i);
i++;
}
printf("Sum of squares of first %d natural numbers = %d",
n, sum);
return 0;
}Without using a loop
We can also find the sum of squares of N natural numbers without using the loop. The formula is given as,
The sum of squares of N natural numbers = n(n+1)(2n+1)/6;
#include<stdio.h>
int main()
{
int n;
printf("Enter n value: ");
scanf("%d", &n);
int sum = n*(n+1)*(2*n+1)/6;
printf("Sum of squares of first %d natural numbers = %d",
n, sum);
return 0;
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