我想问一下,这三种声明的差别是什么呢?
#include <iostream>
int sum1(int n) {
int s = 0;
while (n > 0) {
s++;
n--;
}
return s;
}
int input;
int sum2() {
int s = 0;
while (input > 0) {
s++;
input--;
}
return s;
}
int sum3() {
int s = 0;
for (int i = input; i > 0; i--)
s++;
return s;
}
int main() {
input = 5;
std::cout << sum1(input) << '\n';
std::cout << sum2() << '\n';
std::cout << sum3() << '\n';
}