The central processing unit or processor is the main component of a computer system / machine where the low level programs or machine codes are executed. CPU acts like the brain of a computer system.
All CPUs execute the programs by following the four basic steps of information processing: fetch, decode, execute, and write back. The fetch step involves retrieving program instructions from memory. During the decode step, these program instructions are decoded and divided into parts relevant to different sections of the CPU. In the next step, the arithmetic logic unit (ALU) and floating-point unit (FPU) of the Central Processing Unit work in perfect coordination to execute the program instructions. In the final step, the results of program execution are written back to the memory.