Question

Write a program in C that creates an array of 100 random numbers from 0-99. The program sums the random numbers and prints the sum.  It then writes the numbers to a new file using open, close and write. Then looks in the current directory for files that match the pattern “numbers.XXXX”. For each file, open the file and read the file. You can assume that the file will contain 100 integers. Sum the integers. Print the filename and the sum of the integers.

Other requirements:

1. Input—The program has no input data (it uses standard function to generate sequence of random numbers).
2. Output—The program prints the sum of the array. The program creates a file called numbers.XXXX where XXXX is the sum of the numbers in the file.
3. Program structure—The program has needs only one function: int main(void)

Hints:

Remember to initialize any sum variable to 0

rand() will return a random number too big for 0-99. Use modulo to reduce the range.

Answer 1

Code :

#include <stdio.h>
#include <stdlib.h>
int main()
{
int lowerlimit=0;
int upperlimit=99;
int count=100;
int sum=0;
int a[100];
for(int i=0;i<count;i++)
{ //creating random numbers and entering in array.
int temp = (rand()%(upperlimit-lowerlimit+1))+lowerlimit;
a[i]=temp;
}
printf("Random numbers are : \n");
for(int i=0;i<count;i++)
{ //printing random numbers.
printf("%d ",a[i]);
}

for(int i=0;i<count;i++)
{   
sum+=a[i]; //calculating the sum of random numbers.
}
printf("\nSum of random numbers is : ");
printf("%d ",sum);

FILE *file; //as the sum of random numbers is 5184 so file name is numbers5184.
file=fopen("numbers5184.txt","w"); //creating the file.
for(int i=0;i<count;i++)
{
putw(a[i], file); //entering random numbers in file.
}
fclose(file);

file=fopen("numbers5184.txt","r")
int num;
while ((num = getw(fptr))!=EOF)
{
printf("%d\n",num); //printing numbers from file.
}
fclose(file);
  
return 0;
}

Screenshots of code and output :