C Program to Print numbers from 1 to 10 and 10 to 1 using Do-While Loop

Last update on July 30 2025 12:56:21 (UTC/GMT +8 hours)

1. Print Numbers Using Do-While Loop

Write a C program to print numbers from 1 to 10 and 10 to 1 using a do-while loop.

Sample Solution:

C Code:

#include <stdio.h>

int main() {
    int i = 1;  // Initialize the loop control variable to 1

    // Print numbers from 1 to 10
    printf("Print numbers from 1 to 10:\n");
    do {
        printf("%d ", i);  // Print the current value of i
        i++;  // Increment i for the next iteration
    } while (i <= 10);  // Continue the loop as long as i is less than or equal to 10

    printf("\n");  // Move to the next line for better formatting

    i = 10;  // Reset i to 10 for the second part of the program

    // Print numbers from 10 to 1
    printf("\nPrint numbers from 10 to 1:\n");
    do {
        printf("%d ", i);  // Print the current value of i
        i--;  // Decrement i for the next iteration
    } while (i >= 1);  // Continue the loop as long as i is greater than or equal to 1

    return 0;  // Indicate successful program execution
}

Sample Output:

Print numbers from 1 to 10:
1 2 3 4 5 6 7 8 9 10

Print numbers from 10 to 1:
10 9 8 7 6 5 4 3 2 1

Explanation:

Here is the break down of the above code step by step:

#include <stdio.h>: This line includes the standard input-output library, which is necessary for using functions like "printf() and "scanf()".
int main() {: This line marks the beginning of the "main()" function, which is the entry point of every C program.
int i = 1;: This line declares an integer variable 'i' and initializes it to 1. This variable will be used as a loop control variable.
// Print numbers from 1 to 10: This comment indicates the intention of the following code block.
do {: Marks the beginning of a do-while loop. The code inside the curly braces will be executed at least once before checking the loop condition.
printf("%d ", i);: Prints the current value of 'i' using the "printf()" function.
i++;: Increments the value of 'i' by 1 for the next iteration.
} while (i <= 10);: Specifies the loop condition. The loop will continue to execute as long as the value of i is less than or equal to 10.
printf("\n");: Moves to the next line for better formatting.
i = 10;: Resets the value of 'i' to 10 for the second part of the program.
// Print numbers from 10 to 1: Comment indicating the intention of the following code block.
do {: Starts another do-while loop.
printf("%d ", i);: Prints the current value of 'i'.
i--;: Decrements the value of 'i' by 1 for the next iteration.
} while (i >= 1);: Specifies the loop condition for the second loop. It continues as long as i is greater than or equal to 1.
return 0;: Indicates that the program executed successfully. The 0 here is typically used to indicate successful execution.
}: Marks the end of the "main()" function.

In summary, this program uses two do-while loops to print numbers in ascending order (1 to 10) and then in descending order (10 to 1), separated by a newline for better output formatting. The loop control variable i is incremented in the first loop and decremented in the second loop. The program then returns 0, indicating successful execution.

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to print numbers from 1 to 20 in ascending and then descending order using a do-while loop.
Write a C program to print only prime numbers from 1 to 50 using a do-while loop.
Write a C program to print numbers from 1 to 10 in reverse order without using the decrement operator.
Write a C program to print numbers from 1 to 10 but skip every third number using a do-while loop.

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