Problems: First Programs

Alice sells books at a school fair and needs a sign for her stall. The sign is two lines: a fixed banner, then the word Stall and her stall number.

Input. One line with one integer n, the stall number.

Output. Two lines. The first is exactly === PROGSITY ===. The second is Stall, one space, then n.

Constraints. 1 <= n <= 999.

Sample. Input 7 gives === PROGSITY === then Stall 7.

#include <stdio.h>

int main(void)
{
    int n;
    scanf("%d", &n);

    /* Your two printf calls go here. */

    return 0;
}

Maria wants her three subject marks printed as a small card, one subject per line, using three separate printf calls.

Input. One line with three integers a b c, the marks for Maths, Physics and Chemistry.

Output. Three lines: Maths: a, Physics: b, Chemistry: c. One space after each colon.

Constraints. 0 <= a, b, c <= 100.

Sample. Input 90 85 77 gives Maths: 90, Physics: 85, Chemistry: 77.

#include <stdio.h>

int main(void)
{
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);

    /* Three printf calls, one per subject. */

    return 0;
}

Bob's report line has to carry a tab and a pair of quotation marks. A bare quote would end the string early, so it needs an escape.

Input. One line with one integer s, Bob's score.

Output. Two lines. The first is Bob wrote:, one tab, then "Hello, C." with the quotes printed. The second is Score:, one tab, then s.

Constraints. 0 <= s <= 100.

Sample. Input 95 gives Bob wrote:, a tab, "Hello, C.", then Score:, a tab, 95.

#include <stdio.h>

int main(void)
{
    int s;
    scanf("%d", &s);

    /* Two printf calls, with two escape sequences in the first. */

    return 0;
}

Bob's doubling program has three syntax errors and nothing else wrong. Repair it until it compiles, then check that it prints the right answer.

Input. One line with one integer n.

Output. One line: Double of n is 2n, with both numbers filled in.

Constraints. 0 <= n <= 1000.

Sample. Input 21 gives Double of 21 is 42.

#include <stdio.h>

int main(void)
{
    int n
    scanf("%d", &n);
    Printf("Double of %d is %d\n", n, n * 2);
    return 0;

This program compiles on the first try and is still wrong. Maria wants the area of a square tile, and the program prints the distance around it.

Input. One line with one integer s, the side of the square in centimetres.

Output. One line: Area is X, where X is the area in square centimetres.

Constraints. 1 <= s <= 100.

Sample. Input 4 gives Area is 16. The starter prints 16 for this input too, which is the trap.

#include <stdio.h>

int main(void)
{
    int s;
    scanf("%d", &s);

    printf("Area is %d\n", 4 * s);

    return 0;
}

Zara was taking notes by hand and wrote the names of the symbols instead of the symbols. Put the real symbols back, so the program prints the expression and its value.

Input. One line with two integers a b.

Output. One line, exactly: (a + b) * 2 = X, with the two numbers and the answer filled in.

Constraints. 0 <= a, b <= 1000.

Sample. Input 7 4 gives (7 + 4) * 2 = 22.

#include <stdio.h>

int main(void)
{
    int a, b;
    scanf("%d %d", &a, &b);

    /* Print: open-paren, a, space, plus, space, b, close-paren,
       space, asterisk, space, 2, space, equals, space, the value. */
    printf("%d\n", 0);

    return 0;
}

Maria is building a tool that shows the code of any key. Read one character and print its decimal ASCII code.

Input. One line holding exactly one character, which may be a space.

Output. One line with its decimal ASCII code.

Constraints. The character is printable ASCII, code 32 to 126.

Sample. Input A gives 65.

#include <stdio.h>

int main(void)
{
    char ch;
    scanf("%c", &ch);

    /* One printf. Which specifier do you need? */

    return 0;
}

Amara is checking a form where three digits arrive as characters, with nothing between them. Add up what they stand for.

Input. One line with exactly three digit characters and no spaces.

Output. One line with the sum of the three digit values.

Constraints. Each character is '0' to '9'.

Sample. Input 407 gives 11.

#include <stdio.h>

int main(void)
{
    char a, b, c;
    scanf("%c%c%c", &a, &b, &c);

    /* Trick two, three times. */

    return 0;
}

Kenji prints a small receipt footer. It carries a Windows path, a percentage and a quoted note, which is three escapes in three lines.

Input. One line with one integer n, the discount percentage.

Output. Three lines. Path:, a tab, then C:\progsity\bin. Then Discount:, a tab, n, a percent sign. Then Note:, a tab, and "keep the receipt" in quotes.

Constraints. 0 <= n <= 100.

Sample. Input 15 gives Discount:, a tab, then 15% on the middle line.

#include <stdio.h>

int main(void)
{
    int n;
    scanf("%d", &n);

    /* Three printf calls. Watch the backslashes and the percent sign. */

    return 0;
}

Zara is labelling shelves and needs two facts about a letter: where it sits in the alphabet, and how it looks in capitals. No library function, only arithmetic.

Input. One line with one small letter, 'a' to 'z'.

Output. Two lines. The first is the letter, then is letter number, then its position, with a counting as 1. The second is uppercase:, one space, and the letter in capitals.

Constraints. The input is always a small letter.

Sample. Input c gives c is letter number 3 then uppercase: C.

#include <stdio.h>

int main(void)
{
    char ch;
    scanf("%c", &ch);

    /* Two printf calls, and two of the three tricks. */

    return 0;
}