Question

I need this written in both shell script and C. Assume that it goes on infinitely

Program 3: nested loop. e.g. 1*2 + 2*3 + 3*4 + ...(n-1)*n  (Only nested loops)

Answer 1

C Program:

#include <stdio.h>

int main(void) {
  printf("Enter Size(N) : ");
  int N, sum = 0;
  scanf("%d", &N);

  for (int i=0; i<=N-1; i++)
  {
    for (int j=i+1; j<=N; j++)
    {
      if ((j-i) == 1)
      {
        sum += (i*j);
      }
    }
  }

  printf("Sum : %d", sum);
  return 0;
}

Shell Script Program:

echo "Enter Size(N)"
read N

i=1
sum=0

for (( i = 1; i <= N-1; i++ ))      ### Outer for loop ###
do
    for (( j = i+1 ; j <= N; j++ )) ### Inner for loop ###
    do
    if [ $((j - i)) -eq 1 ]
    then
          sum=$((sum + (i * (j))))
    fi
    done
    
done

echo "Sum : "$sum

Output:

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