Measuring the clock ticks and CPU seconds required in the execution of a function

In this recipe, we will learn how to find out the clock ticks and CPU seconds that are required in the execution of a function. We will create a program that contains a function. This function will simply run a nested loop and we will find out the time required to run it. To do so, we will make use of the clock() function. 

The clock() function returns the processor time that is consumed by the program. Essentially, this time is dependent on the technique that the operating system uses in allocating the resources to the process. More precisely, the function returns the number of clock ticks elapsed from the time the program is invoked. The function does not require any parameters and returns either the processor time that is required in running certain statements or returns -1 if there is any failure.

The time returned by the function is measured in CLOCKS_PER_SECs of a second, where CLOCKS_PER_SEC varies as per the operating system and its value is around 1,000,000. So, in order to find the number of seconds used by the CPU, the number of clock ticks returned by the function is divided by CLOCKS_PER_SEC.

The value returned by the clock() function is of the clock_t data type. The clock_t data type is used to represent the processor time.