int, double and char

Each type has its own format code

int holds whole numbers and prints with %d. double holds decimals and prints with %f; %.2f shows exactly 2 decimal places. char holds one character in single quotes, like 'A', and prints with %c.

Using the wrong code (say %d for a double) doesn't stop the program, it just prints garbage. Matching codes to types is your job.

Three types, three codes

#include <stdio.h>

int main() {
    int qty = 3;
    double price = 49.5;
    char grade = 'A';
    printf("%d x %.2f = %.2f\n", qty, price, qty * price);
    printf("Grade %c\n", grade);
    return 0;
}

1. Line 4: A whole number.
2. Line 5: A decimal number.
3. Line 6: One character, written in single quotes.
4. Line 7: Three placeholders, filled in order. %.2f rounds to 2 decimal places.
5. Line 8: %c prints the character.

How many decimals?

#include <stdio.h>

int main() {
    double r = 2.0 / 3;
    printf("%.3f\n", r);
    return 0;
}

What does this print?

• 0.667
• 0.666
• 0.67

Characters are numbers too

#include <stdio.h>

int main() {
    char c = 'A';
    printf("%c %d\n", c + 2, c);
    return 0;
}

What does this print?

• C 65
• A 65
• A+2 A

Exercise: A canteen bill

Use variables: 2 samosas at 15.50 each and 1 tea at 12.00.

Print the total with two decimals: Total: Rs 43.00

Then print the first letter of your bill code, the char 'B': Code: B