Generate an even squares between 1 to n using for loop in C Programming

Even square numbers are the squares of even integers like 2², 4², 6², 8², which result in 4, 16, 36, 64, 100, and so on. In this tutorial, we will generate even squares between 1 to n using a for loop in C programming.

Syntax

for (initialization; condition; increment) {
    // Loop body
}

Algorithm

START
Step 1: Declare variables a and n
Step 2: Read number n from user
Step 3: Use for loop to generate even squares
        For a = 2; a*a <= n; a += 2
        Print a*a (square of even numbers)
STOP

Example 1: Generate Even Squares Between 1 to n

This program generates all even squares from 1 to a given number n −

#include <stdio.h>

int main() {
    int a, n;
    printf("Enter a number for n: ");
    scanf("%d", &n);
    
    printf("Even squares between 1 and %d are:
", n);
    for (a = 2; a * a <= n; a += 2) {
        printf("%d
", a * a);
    }
    
    return 0;
}

Enter a number for n: 200
Even squares between 1 and 200 are:
4
16
36
64
100
144
196

Example 2: Generate Even Cubes Between 1 to n

Similarly, we can generate even cubes by calculating a³ for even values of a −

#include <stdio.h>

int main() {
    int a, n;
    printf("Enter a number for n: ");
    scanf("%d", &n);
    
    printf("Even cubes between 1 and %d are:
", n);
    for (a = 2; a * a * a <= n; a += 2) {
        printf("%d
", a * a * a);
    }
    
    return 0;
}

Enter a number for n: 300
Even cubes between 1 and 300 are:
8
64
216

How It Works

• The for loop starts with a = 2 (first even number)
• The condition a * a <= n ensures we only generate squares within the given range
• The increment a += 2 moves to the next even number
• Inside the loop, a * a calculates the square of the current even number

Conclusion

Generating even squares using a for loop is efficient and straightforward. By incrementing the loop variable by 2 and starting from 2, we ensure only even numbers are squared within the specified range.