Regarding cumulative sum

#1

Sir, how to calculate the cumulative sum as csum[j]-csum[i-1; please clear my doubt]

#2

Hey @devsumanprasad Once after creating csum array
You have to use nested loops
for(int i=0;i<n;i++){
for(int j=i;j<n;j++){
if(i>=1)sum=csum[j]-csum[i-1];
else sum=csum[j];
}
}