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

Chapter 5 ■ Programs with Repetition Logic
Like before, we get the first number before we enter the while loop. This is to ensure that the
while condition makes sense (is defined) the first time. It would not make sense if num had no
value. If it is not 0, we enter the loop. Inside the loop, we process the number (compare it with
bigNum, etc.) after which we get another number. This number is then used in the next test of the
while condition. When the while condition is false (num is 0), the program continues with the
print statement after the loop.
This algorithm is implemented as shown in Program P5.4.
Program P5.4
//find the largest of a set of numbers entered
#include <stdio.h>
int main() {
int num, bigNum = 0;
printf("Enter a number (0 to end): ");
scanf("%d", &num);
while (num != 0) {
if (num > bigNum) bigNum = num; //is this number bigger?
printf("Enter a number (0 to end): ");
scanf("%d", &num);
}
printf("\nThe largest is %d\n", bigNum);
}
Let us “step through” this program using the sample data entered at the beginning of this
section. For easy reference, the data was entered in the following order:
36 17 43 52 50 0
Initially, num is undefined and bigNum is 0. We show this as:
num bignum 0
36 is entered and stored in num;
num is not 0 so we enter the while loop;
num (36) is compared with bigNum (0);
36 is bigger so bigNum is set to 36, giving:
num 36 bignum 36
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