C++ 错误 "expected initializer before <variablename>"

Question

程序员们下午好，

我是 C++ 的新手。我使用 eclipse，我有一个作业要求我在给定恒定的出生率、死亡率、移民率和当前人口的情况下计算未来人口。

我收到两个错误。 1) 在 "float SECONDSINAYEAR;" 行我得到错误 "expected initializer before BIRTHRATEPERSEC" 2) 在 "CURRENTPOPULATION = 318933342;" 行我收到错误消息“'futurepopulation' 未在此范围内声明”

#include <iostream>
using namespace std;

float main(void) {

//declaration of variables
float BIRTHRATEPERSEC;
float DEATHRATEPERSEC;
float IMMIGRANTRATEPERSEC;
float CURRENTPOPULATION;
float SECONDSINAYEAR;
float futurepopulation;

// Initialize constants
BIRTHRATEPERSEC = .5;
DEATHRATEPERSEC = -.1428571429;
IMMIGRANTRATEPERSEC = .04167;
CURRENTPOPULATION = 318933342;
SECONDSINAYEAR = 31536000;

// DO calculations
float futurepopulation = (CURRENTPOPULATION + (SECONDSINAYEAR * (BIRTHRATEPERSEC + DEATHRATEPERSEC + IMMIGRANTRATEPERSEC)));

//print output

cout << "The future population is " + futurepopulation <<endl;
return 0;

}

我该怎么办？谢谢！

Answer 1

第一个问题是您的 main 应该 return 一个整数，而不是一个浮点数。

您还声明了两次 float futurepopulation，一次是用其他变量，一次是求和。

最后一个问题是，在 C++ 中，您不能以这种方式将数字添加到字符串中，正确的语法是 cout << "The future population is " << futurepopulation <<endl;

C++ 错误 "expected initializer before <variablename>"

C++ error "expected initializer before <variablename>"

initializer