Objective

Make counter.h safe to include more than once, then implement the three functions it declares.

Steps

• Write counter.h and counter.c.
• Keep the counter type and the three function signatures from the starter.
• Protect the whole header with an include guard. Grademe includes it twice in the same source file.
• counter_reset stores zero in the counter.
• counter_add adds amount to the current value. Negative amounts are valid.
• counter_value returns the current value without modifying the counter.
• Do not use global or static storage. Two counter values must remain independent.

Objective

Make counter.h safe to include more than once, then implement the three functions it declares.

Steps

• Write counter.h and counter.c.
• Keep the counter type and the three function signatures from the starter.
• Protect the whole header with an include guard. Grademe includes it twice in the same source file.
• counter_reset stores zero in the counter.
• counter_add adds amount to the current value. Negative amounts are valid.
• counter_value returns the current value without modifying the counter.
• Do not use global or static storage. Two counter values must remain independent.