A semantic error occurs when the program runs without crashing (it’s syntactically correct), but it does not do what the programmer intended — because the logic or meaning of the code is wrong.
semantic errors are errors that occur when the code written by the programmer makes no sense to the compiler, even though it is syntactically correct. They are different from syntax errors, which indicate errors in the structure of the program, as semantic errors are related to the meaning and implementation of the program.
Semantic errors are similar to logic errors in that semantic errors occur when mistakes are made in the program’s behavior or logic, but they are not exactly the same. Semantic errors refer to errors in the meaning or interpretation of the code, where the code does not correctly convey the intended functionality or behavior. These errors are more subtle and more complex to detect than syntax or logic errors.
For example,
- Using a string instead of an integer or accessing an array index that is out of bounds can cause semantic errors.
- Uninitialized variables and type incompatibility are other common types of semantic errors.
- Misinterpreting or misunderstanding the requirements or specifications of a program.
- Flaws in algorithm design or implementation.
- Assigning or manipulating variables of incompatible data types.
- Improper usage of external libraries or APIs due to misunderstandings of their functionality or incorrect integration into the codebase.
- Lack of clear and comprehensive documentation, comments, or code annotations.
#include <iostream>
int main() {
int a, b, c;
a * b = c;
// This will generate a semantic error
return 0;
}
prog.cpp: In function ‘int main()’:
prog.cpp:6:13: error: lvalue required as left operand of assignment
a * b = c;
^
when an expression is placed on the left side of an assignment operator (=), it can cause a semantic error even if the code is written correctly according to syntax rules. This is because the compiler cannot interpret the code correctly, leading to errors in program execution.