Following is the procedure to use time() functions in C. These functions help us to calculate total time taken (in seconds) to execute a set of statements. This is very helpful if we are testing the efficiency of any algorithm / methodology: Include time.h header in your C program. i.e., write #include<time.h> statement before main() function. Inside main(), define two variables t1 and t2 whose data type is time_t. i.e, write time_t t1, t2; t1 is used to record initial time (in seconds) and t2 is used to record elapsed time (in seconds) Use t1=time(NULL); before the start of the algorithm/ methodology that you want to test. After writing algorithm/ methodology, use t2=time(NULL); Total time taken can now be calculated as: t2-t1. Following sample example shows the usage of time() functions in C programs: #include<stdio.h> #include<time.h> main() { time_t t1, t2; int flag=0; ...