Q.Write a C program to accept four numbers and compute their sum and average. The textbook presents this worked program, transcribed exactly as printed (including its printed errors):

#include<stdio.h>  
void main()  
{  
int num1, num2, num3, num4, sum;  
float averag;  
printf("Enter Four Numbers\n");  
scanf("%d%d%d%d", &num1, &num2, &num3, &num4);  
sum=num1+num2+num3+num4;  
averag=sum/4.0;  
printf("sum=%d\n average=%f\n", sum, averag)  
}  

Sample output printed in the textbook:

Enter Four Numbers  
18   22   14   26  
Sum = 80  
Average = 20.000000  

The four integers are read with a single scanf, added into an integer sum, and the average is obtained as a floating-point value by dividing the sum by 4.0 (so the fractional part is not lost). For 18, 22, 14 and 26 the sum is 80 and the average is 20.0. …

[!TLDR]

Read four integers, add them, and print the sum (80) and the floating-point average (20.000000).

Averaging shows why the type of a division matters in C. The four values are stored in int variables and their total, sum, is also an int. If the average were written as sum/4 the result would be truncated to an integer; writing sum/4.0 forces the division to be done in floating point, so the exact average is kept. The average variable is therefore declared float and printed with the %f specifier, while the integer sum is printed with %d. …