Which of the shell command pipelines below is equivalent to the following program? int main() { file *fp, *pp; char line [100]; fopen("file1","r"); assert(fp ! = null); popen("wc -1", "w"); assert(pp ! = null); fp = pp = while (fgets( line,100, fp)! = null) fputs(line, pp) fclose(fp); pclose(pp); } assume that all of the appropriate #includes have been done fopen file1 wc -1 cat file1 t wc -1 ls -l file1 wc -1 cat file1 none of the other options is correct

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Which describes which ctso each student should join

Cylinder heads with four valves flow more air than those with two valves because they