Find the minimum value among three given numbers.
To find the minimum of three numbers a, b, and c:
Numbers: a = 10, b = 5, c = 8
Step 1: Is a < b AND a < c?
10 < 5? NO → a is not minimum
Step 2: Is b < a AND b < c?
5 < 10? YES AND 5 < 8? YES → b is minimum!
Result: Minimum is 5
Accept three integers as input
Print the output as "Minimum is ___"
-10^15 <= INPUT <= 10^15
#include <iostream> #include <cmath> // Note: min() is actually in <algorithm>, not <cmath> using namespace std; int main() { long long a, b, c, minimum; cin >> a >> b >> c; // Method 1: Using built-in min() function (commented out) // minimum = min(min(a, b), c); // Requires <algorithm> // Method 2: Using if-else logic if (a < b && a < c) minimum = a; else if (b < a && b < c) minimum = b; else minimum = c; cout << "Minimum is " << minimum; return 0; }
The code includes <cmath>, but the min() function is actually defined in <algorithm>. The code may still work on some compilers because <cmath> sometimes transitively includes <algorithm>, but this is compiler-dependent and not guaranteed by the C++ standard. For portable code, always include <algorithm> when using min() or max().
<) to compare valuesmin() function vs manual comparisonDecision Tree:
Is a < b AND a < c?
├── YES → minimum = a ✓ (DONE)
└── NO → Continue...
Is b < a AND b < c?
├── YES → minimum = b ✓ (DONE)
└── NO → minimum = c ✓ (DONE)
Logic: If neither a nor b is smallest, then c must be!
Why the Else Clause Works:
a is not smaller than both others → it's not minimumb is not smaller than both others → it's not minimumc must be the minimum (or equal to minimum)C++ provides the min() function from the <algorithm> header:
#include <iostream> #include <algorithm> // Required for min() function using namespace std; int main() { long long a, b, c; cin >> a >> b >> c; // Nested min() - find min of (a,b), then compare with c long long minimum = min(min(a, b), c); cout << "Minimum is " << minimum; return 0; }
How it works:
min(a, b) → returns the smaller of a and bmin(result, c) → compares that result with cC++11 and later: You can also use initializer lists:
long long minimum = min({a, b, c}); // Requires C++11 or later
⚠️ Important Note:
The code includes <cmath> instead of <algorithm>, but it still works on many compilers because <cmath> sometimes implicitly includes <algorithm>. However, this is non-standard behavior! Always use <algorithm> when you need min() or max() functions for portability.
| Aspect | Manual If-Else Logic | Built-in min() Function |
|---|---|---|
| Code Length | Longer (7-8 lines) | Shorter (1 line) |
| Readability | Clear logic flow | More concise |
| Performance | Similar (compiler optimizes both) | Similar |
| Learning Value | High (understand comparison logic) | Medium |
| Flexibility | Easy to add custom logic | Limited customization |
| Error Prone | More chances for logic errors | Less error-prone |
| Best For | Learning, interviews, custom needs | Production code, quick solutions |
// ❌ WRONG: Only checks if a < b, not if a < c if (a < b) minimum = a; // What if c is smaller than a?
// ❌ WRONG: a must be smaller than BOTH b and c if (a < b || a < c) // Using OR is incorrect! minimum = a;
> instead of < for minimumint for large values instead of long longApproach 1: Simplified If-Else (Assuming a is minimum first)
long long minimum = a; // Assume a is minimum if (b < minimum) minimum = b; // Update if b is smaller if (c < minimum) minimum = c; // Update if c is smaller cout << "Minimum is " << minimum;
Approach 2: Ternary Operator (Nested)
long long minimum = (a < b) ? ((a < c) ? a : c) : ((b < c) ? b : c); cout << "Minimum is " << minimum;
Approach 3: Using Array and Loop (Scalable)
long long arr[3] = {a, b, c}; long long minimum = arr[0]; for (int i = 1; i < 3; i++) { if (arr[i] < minimum) minimum = arr[i]; } cout << "Minimum is " << minimum;