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

Chapter 5 ■ Programs with Repetition Logic
Program P5.3
//print the sum and count of several numbers entered by a user
#include <stdio.h>
int main() {
int num, sum = 0, n = 0;
printf("Enter a number (0 to end): ");
scanf("%d", &num);
while (num != 0) {
n = n + 1;
sum = sum + num;
printf("Enter a number (0 to end): ");
scanf("%d", &num);
}
printf("\n%d numbers were entered\n", n);
printf("The sum is %d\n", sum);
}
The following is a sample run of the program:
Enter a number (0 to end): 24
Enter a number (0 to end): 13
Enter a number (0 to end): 55
Enter a number (0 to end): 32
Enter a number (0 to end): 19
Enter a number (0 to end): 0
5 numbers were entered
The sum is 143
Comments on Program P5.3
• We declare and initialize n and sum to 0 before the while loop.
• The statement
n = n + 1;
adds 1 to n. We say n is incremented by 1. Suppose n has the value 3.
• When the right-hand side is evaluated, the value obtained is 3 + 1 = 4.
This value is stored in the variable on the left-hand side, that is, n. The net
result is that 4 is stored in n.
• This statement is placed inside the loop so that n is incremented each time
the loop body is executed. Since the loop body is executed when num is not 0,
the value of n is always the amount of numbers entered so far.
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