#include <iostream>
#include <cassert>
#include <string>
using namespace std;
double text;
string letterGrade(double text)
{
string result;
if (text >= 90.0)
result = "A";
else if (text >= 80.0)
result = "B";
else if (text >= 70.0)
result = "C";
else if (text >= 60.0)
result = "D";
else result = "F";
return result;
}
int main()
{
assert("A" == letterGrade(90.0));//测试结果值是否和预期值相等assert
assert("B" == letterGrade(80.0));//若程序执行后未输出Assertion failed，即结果值==预期值。
assert("C" == letterGrade(70.0));
assert("D" == letterGrade(60.0));
assert("F" == letterGrade(59.9));
//输出测试
while (1)
{
cout << "请赋值letterGrade text:";
cin >> text;
cout << "即将执行函数letterGrade(" << text << ")..." << endl;
cout << "等级为：" << letterGrade(text) << endl;
}
return 0;
}