C Programming Absolute Beginner's Guide (3rd Edition)

intAnswer = x % y; // This calculates the remainder (4)

printf("%d modulus (i.e. remainder of) %d equals %d", x, y,

intAnswer);

return 0;

}

The last math statement in this program might be new to you. If you need the remainder after integer
division, use C’s modulus operator (%). Given the values just listed, the following statement puts a 4
in intAnswer:

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ansMod = x % y; /* 4 is the remainder of 19 / 5 */

You now know the three ways C divides values: regular division if a float is on either or both sides
of the /, integer division if an integer is on both sides of the /, and modulus if the % operator is used
between two integers.

Tip

You can’t use % between anything but integer data types.

The following short program computes the net sale price of tires:

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// Example program #2 from Chapter 9 of Absolute Beginner's Guide to

// C, 3rd Edition

// File Chapter9ex2.c

/* This program asks the user for a number of tires and price per

tire. It then calculates a total price, adding sales tax. */

// If you find you use a sales tax rate that may change, use #define

// to set it in one place

#include <stdio.h>

#define SALESTAX .07

main()

{

// Variables for the number of tires purchased, price,

// a before-tax total, and a total cost

// with tax

int numTires;

float tirePrice, beforeTax, netSales;

/* Get the number of tires purchased and price per tire. */

printf("How many tires did you purchase? ");

scanf(" %d", &numTires);

printf("What was the cost per tire (enter in $XX.XX format)? ");

scanf(" $%f", &tirePrice);