What situations can cause Golang function type errors?

Function type error occurs when the function parameter or return value type does not match the declaration. The reasons include: 1. Parameter type mismatch; 2. Return value type mismatch. Fix: 1. Make sure the parameter type matches the definition; 2. Make sure the return value type matches the definition.

Golang function type error: causes and solutions

Function type error is a common error in Go programming. It occurs when a function's parameters or return value do not match its type declaration. It is crucial to understand what causes these errors in order to fix them correctly.

1. Parameter type mismatch

This error occurs when the parameter type of the function call is different from the parameter type of the function definition. For example:

func greet(name string) {
    fmt.Println("Hello", name, "!")
}

func main() {
    // 错误：name 类型为 int，需要 string
    greet(123)
}

To fix this error, make sure the parameter types of the function call match the function definition.

2. Return value type mismatch

This error occurs when the actual type returned by the function is different from the return type defined by the function. For example:

func sum(a, b int) int {
    return a + b
}

func main() {
    // 错误：函数返回 float64，需要 int
    result := sum(1, 2)
    fmt.Println(result)
}

To fix this error, make sure that the actual type returned by the function matches the function's defined return type.

Practical case

Consider the following function:

func calculateArea(length float64, width float64) float64 {
    return length * width
}

Error case:

Try using the following The code calls this function:

area := calculateArea(5, "10")

In this case, a type error occurs because the second parameter is not of type float64.

Correct case:

The second parameter can be converted to float64 type to fix the error:

area := calculateArea(5, float64(10))

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