How many test cases are needed for 100% decision coverage with a gender printing program?

To achieve 100% decision coverage, it is essential to consider every possible outcome of each decision point within the program. In the context of a gender printing program, it is likely that there is a decision based on gender, typically involving a check like "if gender is male then print 'Hello, Sir' else print 'Hello, Ma'am'."

In this scenario, there are two distinct paths based on the gender variable: one for male and one for female. To cover both outcomes and ensure that each branch of the decision point is executed at least once, two test cases are necessary: one case for male and another for female.

Those two test cases enable the program to execute both paths of the decision-making process, thus fulfilling the requirement of 100% decision coverage. If you were to only run one test case, you would only be testing one path and therefore would not achieve complete coverage of the decision point. Hence, the need for two test cases aligns perfectly with the criteria for achieving 100% decision coverage in this scenario.