What is software testing? Why do we need it?

Many folks still confused about what is the stuff, software testing, really is. Software testing Is nothing but to check the similarity/difference between actual results and expected results. If you can say it more elaborately that would be "Software testing is the process of evaluating and verifying that a software does what it is supposed to do". Watts S. Humphrey (July 4, 1927 – October 28, 2010) was an American pioneer in software engineering who was called the "father of software quality". In 1951, Joseph Juran, who is now considered to be the father of software testing, for the first time marked the importance of software quality assurance in his book “Quality control handbook”.

So now the question is do we actually need to test the software? Let's get some memory back then,

• In London, in April 2015 there occurred financial markets crashed due to a software glitch.
• In April 1999, a $1.2B military satellite launching was filled which was caused by a software defect.
• In 1985, in Canada during radiation treatment, a software bug caused 3 patients death and 3 injured.
• In 2015, a fighter plane F-35 was unable to detect and hit its target because of a software glitch.
• China Airbus A300 was crushed because of a software bug that took 260+ innocent people's lives.

There are so many incidents in history. You can easily find them on google.

I hope now you all are acknowledged why we need "Software testing".