How does an IF-THEN-ELSE statement let a program choose between actions?

In computer science, an IF-THEN-ELSE statement is a conditional control structure that enables a program to deviate from a default sequential execution path to follow alternative branches based on specific criteria.1

It functions by evaluating a logical condition. If the condition is true, the program executes the instructions defined in the "THEN" block. If the condition is false, the program instead executes the instructions defined in the "ELSE" block.1

This structure allows programs to make decisions dynamically, much like a recipe that adjusts its steps based on the ingredients available—for example, performing one action if a variable meets a requirement and a different action if it does not. These structures can be nested, where the branches themselves contain further conditionals, loops, or sequences, allowing for the resolution of complex problems through logical branching. At the machine-language level, these decisions are implemented using branch instructions that direct the computer to jump to different points in the program's execution flow.1