C Program to Find the Smallest of Three Numbers

Here we will learn about how to find and print the smallest among any given three numbers (by the user at run-time) with and without using any user-defined function. At the end of the article, we will also see how to find and print the smallest of three numbers using the ternary operator.

Find the smallest of three numbers in C without a user-defined function

Here is the program that will find out the smallest of three numbers provided by the user at run-time.

#include<stdio.h>
#include<conio.h>
int main()
{
    int a, b, c, small;
    printf("Enter three numbers : ");
    scanf("%d%d%d", &a, &b, &c);
    if(a<b)
    {
        if(b<c)
            small = a;
        else
        {
            if(a<c)
                small = a;
            else
                small = c;
        }
    }
    else
    {
        if(b<c)
            small = b;
        else
            small = c;
    }
    printf("\nSmallest number is: %d", small);
    getch();
    return 0;
}

The program was written in the Code::Blocks IDE. Here is the first snapshot of the sample run after a successful build and run:

c find smallest among three numbers

Supply any three numbers and press the ENTER key to see the smallest number among the given three numbers, as shown here in the snapshot given below:

find smallest of three numbers c

Here are some of the main steps used in the above program.

Here is another program to find the smallest of any three numbers in a very simple way. This program is simple and easy to understand.

#include<stdio.h>
#include<conio.h>
int main()
{
    int a, b, c, small;
    printf("Enter three numbers : ");
    scanf("%d%d%d", &a, &b, &c);
    if(a<b && a<c)
        small = a;
    else if(b<a && b<c)
        small = b;
    else
        small = c;
    printf("\nSmallest number is: %d", small);
    getch();
    return 0;
}

Here is the final snapshot of the above program's sample run:

c print smallest of three numbers

In the preceding program, we checked whether the first number, a, is less than both the other numbers, b and c. If it is, then we have initialized the value of a to "small". In this way, we used logic to find the smallest of three numbers in a straightforward manner.

Using function, find the smallest of three numbers

Let's create another program that will do the same task as the above two programs have done but using user-defined functions. Here is the program that uses a user-defined function to return the smallest of any three numbers:

#include<stdio.h>
#include<conio.h>
int getSmall(int, int, int);
int main()
{
    int a, b, c, small;
    printf("Enter three numbers : ");
    scanf("%d%d%d", &a, &b, &c);
    small = getSmall(a, b, c);
    printf("\nSmallest = %d", small);
    getch();
    return 0;
}
int getSmall(int num1, int num2, int num3)
{
    if(num1<num2)
    {
        if(num2<num3)
            return num1;
        else
        {
            if(num1<num3)
                return num1;
            else
                 return num3;
        }
    }
    else
    {
        if(num2<num3)
            return num2;
        else
            return num3;
    }
}

Here is the final snapshot of the sample run:

c find smallest of three using function

Using the ternary operator, find the smallest of three numbers

Let's create another program that will also find and print the smallest of three numbers, but this time using the ternary operator as shown in the program given below:

#include<stdio.h>
#include<conio.h>
int main()
{
    int a, b, c, small;
    printf("Enter three numbers : ");
    scanf("%d%d%d", &a, &b, &c);
    small = (a<b) ? (a<c?a:c) : (b<c?b:c);
    printf("\nSmallest = %d", small);
    getch();
    return 0;
}

Here is the final snapshot of the sample run:

print smallest of three using ternary c

The main logical code is:

small = (a<b) ? (a<c?a:c) : (b<c?b:c);

The description of the above one-line logical code is given below:

C Quiz


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