# C++ program to find greatest of four numbers

In this tutorial, we will write a C++ program to find the greatest of four numbers.

For example

a = 10, b = 50, c = 20, d = 25

The greatest number is b 50

a = 35, b = 50, c = 99, d = 2

The greatest number is c 99

Approach 1

The approach is the traditional way of searching for the greatest among four numbers. The if condition checks whether a is greater and then use if-else to check for b, another if-else to check for c, and the last else to print d as the greatest.

Algorithm

• START
• INPUT FOUR NUMBERS A, B, C, D
• IF A > B THEN
IF A > C THEN
IF A > D THEN
A IS THE GREATEST
ELSE
D IS THE GREATEST
• ELSE IF B > C THEN
IF B > D THEN
B IS THE GREATEST
ELSE
D IS THE GREATEST
• ELSE IF C > D THEN
C IS THE GREATEST
• ELSE
D IS THE GREATEST

C++ Code

Output

```a=10 b=50 c=20 d=25
b is greatest
a=35 b=50 c=99 d=2
c is greatest
```

Approach 2

This approach uses the inbuilt max function.

Here is the syntax of max function

template constexpr const T& max (const T& a, const T& b);

Here, a and b are the numbers to be compared.

Return: Larger of the two values.

For example

std :: max(2,5) will return 5

So, to find out the maximum of 4 numbers, we can use chaining of a max function as follows -

int x = max(a, max(b, max(c, d)));

C++ code

Output

```a=10 b=50 c=20 d=25
b is greatest
a=35 b=50 c=99 d=2
c is greatest
```

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