请帮忙...我对我收到的错误感到困惑 [英] Please help...i am confused with the errors that I am receiving

问题描述

这是我的第一个尝试使用while循环的程序。我尝试编译代码，它给我的错误与代码的那部分没有任何关系，所以我想知道是否有人可以帮助我理解为什么我会收到这些错误。

这是我的代码：

 #include< iostream> 
 #include< string> 
 using namespace std; 
 
 void studentGrade（string）; 
 
 int main 
 {
 string name =zero; 
 int scoreOne，scoreTwo，scoreThree，scoreFour，scoreFive，scoreSix，scoreSeven，scoreEight，scoreNine，scoreTen; 
浮动平均值= 0; //存储所有等级的平均值
浮动总数= 0; //存储成绩总和
 char letterGrade; //存储学生的最终字母等级
 if（name =done）
 {
 cout<< 计划已经完成。 ; 
} 
其他
 {
 studentGrade（姓名）; 
} 
} 
 void studentGrade（字符串名称）
 {
 while（name！=done）
 {
 cout< < 输入学生的姓名。 ; 
 cin>>名称 ; 
 cout<< 输入<<名称<< 有10个考试成绩。 ; 
 cin>> scoreOne>>得分2>>得分三>> scoreFour>> scoreFive>> scoreSix>>得分>> scoreEight>> scoreNine>>得分; 
 total = scoreOne + scoreTwo + scoreThree + scoreFour + scoreFive + scoreSix + scoreSeven + scoreEight + scoreNine + scoreTen; 
平均=总数/ 10; 
 if（平均值> 89.5）
 letterGrade ='A'; 
 else if（平均值> 79.5）
 letterGrade ='B'; 
 else if（平均值> 69.5）
 letterGrade ='C'; 
 else if（平均值> 59.5）
 letterGrade ='D'; 
 else 
 letterGrade ='F'; 
 cout<< 学生的名字：<<名称<<结束
 cout<< 平均等级：<<平均<<结束
 cout<< 字母等级：<< letterGrade<<结束
} 
} 

这些是我收到的错误：

 prog4.cpp：14：警告：扩展初始化程序列表仅适用于-std = c ++ 0x或-std = gnu + + 0x 
 prog4.cpp：16：错误：在'name'之前预期的primary-expression 
 prog4.cpp：16：错误：在'name'之前预期'}'
 prog4.cpp： 16：错误：在'name'之前预期'，'或';'
 prog4.cpp：21：错误：在'if'
 prog4.cpp之前的预期unqualified-id：25：错误：预期不合格-id'之前的'-id'
 prog4.cpp：29：错误：'}'令牌之前的预期声明

f



line 14是：int main



我尝试过：



我尝试添加#include< string>因为我在网上看到了，但它没有改变第二个错误。谢谢你能提供帮助。

解决方案

引用：

第14行： int main

所以看看那一行：

 int main 
 {
 // ... ... 
} 

这不是有效的C / C ++。函数定义包含

1. 返回类型（ int 此处），
   
   
2. 一个名称（ main 此处），
   
   
3. 括号括起来的参数列表（缺失），并且
   
   
4. 用括号括起来的身体。
   
   

所以它一定是

 int main（）
 {
 //函数体
 
 //返回语句（代码中不存在） ）
返回0; 
} 

所有其他错误都来自初始错误，并在修复第一个错误后消失。





修复上述内容后，您将收到一个以前未检测到的新错误：

< pre lang =text>错误：无法将'name.std :: basic_string< ...>'转换为'bool'

std：string 赋值运算符返回对字符串本身的引用，该引用无法转换为 bool 。它可以根据其他解决方案修复（您使用赋值运算符 = 而不是比较运算符 == ） 。

在你的第一个 if 语句中，相等的比较运算符是 == ，而不是 = 。

尝试类似：

  if （name ==   done ）

This is my first program trying to use "while" for a loop. I try to compile the code and it gives me errors that don't have anything to do with that part of the code, so I was wondering if someone could help me understand why I am getting these errors.
Here is my code:

#include <iostream>
#include <string>
using namespace std ;

void studentGrade (string) ;

int main
{
	string name = "zero" ;
	int scoreOne, scoreTwo, scoreThree, scoreFour, scoreFive, scoreSix, scoreSeven, scoreEight, scoreNine, scoreTen ;
	float average = 0 ;			//stores the average of all grades
	float total = 0 ;			//stores sum of grades
	char letterGrade ;			//stores the final letter grade of student
	if (name = "done")
	{
		cout << "Program is done." ;
	}
	else 
	{
		studentGrade (name) ;
	}
}
void studentGrade (string name)
{
	while (name != "done")
	{
		cout << "Enter student's name." ;
		cin >> name ;
		cout << "Enter " << name << "'s 10 test scores." ;
		cin >> scoreOne >> scoreTwo >> scoreThree >> scoreFour >> scoreFive >> scoreSix >> scoreSeven >> scoreEight >> scoreNine >> scoreTen ;
		total = scoreOne + scoreTwo + scoreThree + scoreFour + scoreFive + scoreSix + scoreSeven + scoreEight + scoreNine + scoreTen ;
		average = total / 10 ;
		if (average > 89.5)
			letterGrade = 'A' ;
		else if (average > 79.5)
			letterGrade = 'B' ;
		else if (average > 69.5)
			letterGrade = 'C' ;
		else if (average > 59.5)
			letterGrade = 'D' ;
		else
			letterGrade = 'F' ;
		cout << "Student's name: " << name << endl ;
		cout << "Average Grade: " << average << endl ;
		cout << "Letter Grade: " << letterGrade << endl ;
	}
}

And these are the errors that I am receiving:

prog4.cpp:14: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x
prog4.cpp:16: error: expected primary-expression before ‘name’
prog4.cpp:16: error: expected ‘}’ before ‘name’
prog4.cpp:16: error: expected ‘,’ or ‘;’ before ‘name’
prog4.cpp:21: error: expected unqualified-id before ‘if’
prog4.cpp:25: error: expected unqualified-id before ‘else’
prog4.cpp:29: error: expected declaration before ‘}’ token

f

line 14 being: int main

What I have tried:

I have tried adding in the #include<string> because I saw that online, but it didn't change the second error. Thank you if you can help.

解决方案

Quote:

line 14 being: int main

So have a look at that line:

int main
{
    // ...
}

That is not valid C/C++. A function definition consists of

1. a return type (int here),
   
2. a name (main here),
   
3. a parameter list enclosed by parentheses (missing), and
   
4. the body enclosed by braces.
   

So it must be

int main()
{
    // function body

    // Return statement (does not exist in your code)
    return 0;
}

All the other errors are sourced by the initial error and will vanish after fixing the first error.


After fixing the above you will get a new error which has not been detected before:

error: could not convert ‘name.std::basic_string<...>’ to ‘bool’

The std:string assignment operator returns a reference to the string itself which can't be converted to bool. It can be fixed according to the other solutions (you used the assignment operator = instead of the comparison operator ==).

In your first if statement, the comparison operator for equality is ==, not =.

Try something like:

if (name == "done")

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