C++ Syntax Errors: Learn by Fixing Common Mistakes

#include using namespace std; int a, b, result; int main() { a = 3; b = 2 * a; result = a + b; cout << 'The result of the calculation is ' << result; cout << '\nThe program is complete.\n'; }

ii) For (a) – (d) below, in each case - make the suggested error(s) - build the program - find a line number and a description in the error messages - find and correct the error and run again to make sure that the error message has gone.

(a) change the third line to int a, result; (b) change the line a = 3; to a = 3 (leave out the semi-colon) (c) change cout to count in the first cout statement

(a) After making the suggested error, the program would look like this:

#include using namespace std; int a, result; int main() { a = 3; result = a + b; cout << 'The result of the calculation is ' << result; cout << '\nThe program is complete.\n'; }

When building the program, the error message would be:

error: ‘b’ was not declared in this scope

This error message indicates that the variable 'b' is not declared before its usage.

To correct the error, we can either declare the variable 'b' or remove its usage in the 'result' calculation. Let's remove its usage in this case:

#include using namespace std; int a, result; int main() { a = 3; result = a; cout << 'The result of the calculation is ' << result; cout << '\nThe program is complete.\n'; }

Now, when running the program, the error message should be gone.

(b) After making the suggested error, the program would look like this:

#include using namespace std; int a, b, result; int main() { a = 3 b = 2 * a; result = a + b; cout << 'The result of the calculation is ' << result; cout << '\nThe program is complete.\n'; }

When building the program, the error message would be:

error: expected ‘;’ before ‘b’

This error message indicates that a semicolon is missing after the assignment of 'a'.

To correct the error, we need to add a semicolon after the assignment of 'a':

#include using namespace std; int a, b, result; int main() { a = 3; b = 2 * a; result = a + b; cout << 'The result of the calculation is ' << result; cout << '\nThe program is complete.\n'; }

Now, when running the program, the error message should be gone.

#include using namespace std; int a, b, result; int main() { a = 3; b = 2 * a; result = a + b; count << 'The result of the calculation is ' << result; cout << '\nThe program is complete.\n'; }

When building the program, the error message would be:

error: ‘count’ was not declared in this scope

This error message indicates that the keyword 'count' is not recognized as a valid identifier.

To correct the error, we need to change 'count' to 'cout':

#include using namespace std; int a, b, result; int main() { a = 3; b = 2 * a; result = a + b; cout << 'The result of the calculation is ' << result; cout << '\nThe program is complete.\n'; }

Now, when running the program, the error message should be gone.