C provides several numeric data types for storing numbers — both whole numbers (integers) and decimal numbers (floating point).

🔹 1. int — Integer Type

Used to store whole numbers (no decimal point).

🧩 Example:

#include <stdio.h>

int main() {

    int myNum = 1000;

    printf(“%d”, myNum);

    return 0;

}

✅ Output:

1000

📘 Details:

• Size: usually 2 or 4 bytes
• Range: roughly -32,768 to 32,767 (for 2-byte) or -2 billion to +2 billion (for 4-byte)
• Format specifier: %d or %i

2. float — Single Precision Decimal

Used to store decimal numbers (floating-point values). 

🧩 Example:

#include <stdio.h>

int main() {

    float myNum = 5.75;

    printf(“%f”, myNum);

    return 0;

}

✅ Output:

5.750000

📘 Details:

• Size: 4 bytes
• Precision: about 6–7 digits after the decimal point
• Format specifier: %f

3. double — Double Precision Decimal

Used to store larger or more precise decimal numbers.

🧩 Example:

#include <stdio.h>

int main() {

    double myNum = 19.99;

    printf(“%lf”, myNum);

    return 0;

}

✅ Output:

19.990000

📘 Details:

Size: 8 bytes

Precision: about 15 digits after the decimal point

Format specifier: %lf

⚖️ float vs double

🧠 Tip:
Prefer double for most mathematical and scientific calculations because it’s more accurate.

🧩 Quick Summary Table

✅ Key Points to Remember

• Use int for whole numbers.
• Use float or double for decimals.
• Prefer double for accuracy.
• %d → integer, %f → float, %lf → double.
• Scientific notation uses e or E.