# C Program to find the largest of three numbers

Last updated on September 23, 2020

The following is a C program to find the largest of the three numbers:

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 /********************************************* Program to find the largest of three numbers **********************************************/ #include // include stdio.h library int main(void) { int a, b, c; printf("Enter a: "); scanf("%d", &a); printf("Enter b: "); scanf("%d", &b); printf("Enter c: "); scanf("%d", &c); if(a > b) { if(a > c) { printf("a is largest."); } else { printf("c is largest."); } } else { if(b > c) { printf("b is largest."); } else { printf("c is largest."); } } return 0; // return 0 to operating system } 

Expected Output: 1st run:

 1 2 3 4 Enter a: 45 Enter b: 100 Enter c: 20 b is largest. 

2nd run:

 1 2 3 4 Enter a: -10 Enter b: -81 Enter c: -5 c is largest. 

## How it works #

The program starts off by asking the user to enter three digits (a, b and c).

In line 20, we check whether a is greater than b. If the condition a > b evaluates to true (1) the program control comes to the nested if statement in line 22 and checks whether a > c. If the condition a > c evaluates to true (1), then a is the largest number. Otherwise, c is the largest number.

If the condition in line 20, evaluates to false, then we can say for sure that b > a.

In line 33, we check whether b > c. If it is, then b is the largest number. if the condition fails, then we can conclude that c > b.

Since, b > a and c > b. Therefore, c > b > a. Hence, c is the largest number.