C Program to Find the Largest Number Among Three Numbers

In this example, the largest number among three numbers (entered by the user) is found using three different methods.

To understand this example, you should have the knowledge of following C programming topics:

This program uses only if statement to find the largest number.

Example #1

#include <stdio.h>
int main()
{
    double n1, n2, n3;

    printf("Enter three numbers: ");
    scanf("%lf %lf %lf", &n1, &n2, &n3);

    if( n1>=n2 && n1>=n3 )
        printf("%.2f is the largest number.", n1);

    if( n2>=n1 && n2>=n3 )
        printf("%.2f is the largest number.", n2);

    if( n3>=n1 && n3>=n2 )
        printf("%.2f is the largest number.", n3);

    return 0;
}

This program uses if...else statement to find the largest number.

Example #2

#include <stdio.h>
int main()
{
    double n1, n2, n3;

    printf("Enter three numbers: ");
    scanf("%lf %lf %lf", &n1, &n2, &n3);

    if (n1>=n2)
    {
        if(n1>=n3)
            printf("%.2lf is the largest number.", n1);
        else
            printf("%.2lf is the largest number.", n3);
    }
    else
    {
        if(n2>=n3)
            printf("%.2lf is the largest number.", n2);
        else
            printf("%.2lf is the largest number.",n3);
    }
    
    return 0;
}

This program uses nested if...else statement to find the largest number.

Example #3

#include <stdio.h>
int main()
{
    double n1, n2, n3;

    printf("Enter three numbers: ");
    scanf("%lf %lf %lf", &n1, &n2, &n3);

    if( n1>=n2 && n1>=n3)
        printf("%.2lf is the largest number.", n1);

    else if (n2>=n1 && n2>=n3)
        printf("%.2lf is the largest number.", n2);

    else
        printf("%.2lf is the largest number.", n3);

    return 0;
}

Though, the largest number among three numbers is found using multiple ways, the output of all these program will be same.

Enter three numbers: -4.5
3.9
5.6
5.60 is the largest number.