Practice Problem 9

Read it right next to your computer. Book version bitter C

learn through suffering C language learn through suffering
C language

Basics

Question 1-1

What is the colloquial name for the variable used to count repetitions in a for loop?

Question 1-2

What do we colloquially call a `for` loop that runs forever?

Program reading

What program is intended to display what?
Determine the answer based on the processing content and variable names.

Question 2-1

#include <stdio.h>

int main(void)
{
    int i, price;

    scanf("%d", &price);

    for (i = 1; i <= 9; i++) {
        printf("%d Price Down = %d\n", i, (int)(price * ((10.0 - i) / 10)));
    }

    return 0;
}

Program Manual

Question 3-1

Write a program that uses a for loop to display a multiplication table.

Hint: Use the %2d specifier to align tables.
Hint: You can use a for loop inside another for loop.

explanatory

Question 4-1

Briefly explain how a for loop with a constant number of iterations works.

Fundamentals (Answer Key)

Solution 1-1

Count variable or loop variable

Solution 1-2

Infinite loop

Program Reading (Solution Example)

Solution 2-1

A program that displays prices with discounts ranging from 1% to 9% when a fixed price is entered.

The discount rate is calculated by dividing 10.0 by i, and then dividing the result by 10.

Program Documentation (Example Solution)

Question 2-1

#include <stdio.h>

int main(void)
{
    int x, y;

    for (x = 1; x <= 9; x++) {
        for (y = 1; y <= 9; y++) {
            printf(" %2d ", x * y);
        }
        printf(" \n");
    }
    
    return 0;
}

printf(\n);
You can use `for` loops as well as other blocks (compound statements) in any level of nesting.
　However, please pay attention to code readability.

Descriptive (answer example)

Solution 4-1

Initially set the variable to 1, increment it by 1 each time, and terminate the loop when the variable's value exceeds the specified number of iterations. This achieves a loop with a fixed number of iterations.

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Learning C language through suffering (Kushi C) is
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Part 0: Program Overview

What is a program?