添加第二个匹配条件时出现以下错误
match手臂有不兼容的类型|_____-
match手臂具有不兼容的类型
use std::io;
fn add(x1: i32, x2: i32) -> i32 {
let total = x1 + x2;
println!("Total is: {}", total);
return total;
}
fn subtract(x1: i32, x2: i32) -> i32 {
let total = x1 - x2;
println!("Total is: {}", total);
return total;
}
fn multiply(x1: i32, x2: i32) -> i32 {
let total = x1 * x2;
println!("Total is: {}", total);
return total
}
fn divide(x1: i32, x2: i32) -> i32 {
let total = x1 / x2;
println!("Total is: {}", total);
return total
}
fn calc(operation: fn(num1: i32, num2: i32) -> i32) -> i32 {
let mut input_number = String::new();
println!("Enter Number:");
io::stdin()
.read_line(&mut input_number)
.expect("Not a valid string");
println!("Enter another number:");
let mut input_number2 = String::new();
io::stdin()
.read_line(&mut input_number2)
.expect("Not a valid string");
let parsed_numb1: i32 = input_number.trim().parse().unwrap();
let parsed_numb2: i32 = input_number2.trim().parse().unwrap();
return operation(parsed_numb1, parsed_numb2);
}
fn main() {
let mut input_string = String::new();
println!("Enter either add, substract, multiply, or divide:");
io::stdin().read_line(&mut input_string).unwrap();
match input_string.as_str().trim() {
"add" => {
calc(add);
}
"subtract" => &calc(subtract), // error here
c => println!("Invalid command: {c}"),
}
}
我不确定我借的是否正确，但这似乎是借的问题。它如何能够灵活地处理其他条件，例如乘法、除法和减法。