C Program to Print Number in Words

In this tutorial, we will learn about how to create a program in C that will ask from user to enter any number to convert that number in words (characters). Let's first create a program that will print any given one-digit number (by user at run-time) in words. For example, if user enters 7, then the program prints Seven as output. Later on, you will get the code about printing number (contains more than 1 digit) in words.

Print Single Digit Number in Word

// Print 1 digit Number in Word
// ----codescracker.com----

#include<stdio.h>
#include<conio.h>
int main()
{
    int num;
    printf("Enter the number (less than 10): ");
    scanf("%d", &num);
    printf("\n");
    if(num<10 && num>0)
    {
        if(num==1)
            printf("1=>One");
        else if(num==2)
            printf("2=>Two");
        else if(num==3)
            printf("3=>Three");
        else if(num==4)
            printf("4=>Four");
        else if(num==5)
            printf("5=>Five");
        else if(num==6)
            printf("6=>Six");
        else if(num==7)
            printf("7=>Seven");
        else if(num==8)
            printf("8=>Eight");
        else if(num==9)
            printf("9=>Nine");
    }
    else
        printf("Number must be in between 0 and 10");
    getch();
    return 0;
}

As the program was written under Code::Blocks IDE, therefore here is the sample run after successful build and run:

Let's supply any number under 10 say 8 and press ENTER key to see the output:

Program Explained

• Receive any number as input
• Use if statement and check whether the given number is greater than 0 and less than 10 or not
• If it is, then process the next steps to print the number in words, otherwise exit from the program after printing some message like, number must be in between 0 to 10
• Inside the if block, use if-else statement to check what is the number entered by user, if it is 1, then print it out as 1=>One, if it is 2, then print it out as 2=>Two, ..., if it is 9, then print it out as 9=>Nine

Print Multiple Digit Number in Words

Let's create another program that prints any number (more than one-digit) by its digit-by-digit name (series of words). For example, if user enteres 8127, then program prints its output as Eight One Two Seven.

// Print Multiple digit Number in Words
// ----codescracker.com----

#include<stdio.h>
#include<conio.h>
int main()
{
	long int num, rev=0;
	int digit, rem;
	printf("Enter the number: ");
	scanf("%ld", &num);
	while(num>0)
	{
		rem = num%10;
		rev = rev*10 + rem;
		num = num/10;
	}
	while(rev>0)
	{
		digit = rev%10;
		switch(digit)
		{
			case 1: printf("One ");
				break;
			case 2: printf("Two ");
				break;
			case 3: printf("Three ");
				break;
			case 4: printf("Four ");
				break;
			case 5: printf("Five ");
				break;
			case 6: printf("Six ");
				break;
			case 7: printf("Seven ");
				break;
			case 8: printf("Eight ");
				break;
			case 9: printf("Nine ");
				break;
			case 0: printf("Zero ");
				break;
			default: printf("Something went wrong!!");
				break;
		}
		rev = rev/10;
	}
	getch();
	return 0;
}

Here is the sample run after successful build and run:

Now supply any number say 8127 as input and press ENTER key. Here is the output you will see:

Program Explained

• Receive any number as input from user at run-time
• Here we have reversed the number first, before print it by its digit-by-digit name
• Because, whenever we use the modulous (%) operator to find the remainder or digit of the number, then we will always get last digit of the number
• For example, if user enters 8127 as input, then on using remainder or modulous operator on the number 8127 at first time, that is rem = num%10 where num holds 8127. That is 8127%10 or 7 (last digit of the number) will be initialized to rem
• Therefore, if we will reverse the number then the number becomes 7218, and now when we will calculate its remainder or digit using modulous operator, then we will get 8 as its first remainder which is the first digit of the number, therefore we have done the reverse operation on the given number before actually processing it to print it by its digit-by-digit name
• Now come to the point, after reversing the number, rev is the variable that holds the number in reverse order
• Now find its digit using remainder operator, that is initialize rev%10 or 7218%10 or 8 to a variable say digit
• Use switch case, to check what the variable digit holds as its current value, that is whether it holds 1 or 2 or 3 ... or 9 or 0
• Print its corrensponding word and at last divide the rev or number 7218 by 10 to remove its last digit and process the same steps as told above
• In this way, the number gets printed by its digit-by-digit name on output screen

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