Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

Chapter 5 ■ Programs with Repetition Logic
We can now write Program P5.2, which finds the HCF of two numbers entered.
Program P5.2
//find the HCF of two numbers entered by a user
#include <stdio.h>
int main() {
int m, n, r;
printf("Enter two numbers: ");
scanf("%d %d", &m, &n);
while (n != 0) {
r = m % n;
m = n;
n = r;
}
printf("\nTheir HCF is %d\n", m);
}
Note that the while condition is n != 0 and the while body is the block
{
}
r = m % n;
m = n;
n = r;
The algorithm and, hence, the program, works whether m is bigger than n or not. Using the
example above, if m is 24 and n is 42, when the loop is executed the first time, it will set m to 42 and
n to 24. In general, if m is smaller than n, the first thing the algorithm does is swap their values.
5.3 Keep a Count
Program P5.1 finds the sum of a set of numbers entered. Suppose we want to count how many
numbers were entered, not counting the end-of-data 0. We could use an integer variable n to hold
the count. To get the program to keep a count, we need to do the following:
• Choose a variable to hold the count; we choose n.
• Initialize n to 0.
• Add 1 to n in the appropriate place. Here, we need to add 1 to n each time
the user enters a nonzero number.
• Print the count.
Program P5.3 is the modified program for counting the numbers.
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