#include <iostream.h>


int Add(int first, int second)
{
    std::cout << "In Add(),recieved " << first << "and " << second << "\n";
    return (first+second);
}

int main()
{
    using std::cout;
    using std::cin;
   
    count << "I'm in main()!\n";
    int a, b, c;
    cout << "Enter two numbers: ";
    cin >> a;
    cin >> b;
    cout << "\nCalling Add();\n";
    c=Add(a,b);
    cout << "\nBack in main().\n";
    cout << "c was set to " << c;
    cout << "\nExiting...\n\n";
    getchar();
    return 0;
}

为什么在VC 6.0老是说    error C2653: 'std' : is not a class or namespace name
我照着例题输的。。。
用Dev-C++又可以

你没有写名字空间
在开头要写
using namespace std;

#include <iostream.h>

using namespace std;

int Add(int first, int second)
{
    std::cout << "In Add(),recieved " << first << "and " << second << "\n";
    return (first+second);
}

int main()
{
    using std::cout;
    using std::cin;
   
    cout << "I'm in main()!\n";
    int a, b, c;
    cout << "Enter two numbers: ";
    cin >> a;
    cin >> b;
    cout << "\nCalling Add();\n";
    c=Add(a,b);
    cout << "\nBack in main().\n";
    cout << "c was set to " << c;
    cout << "\nExiting...\n\n";
    getchar();
    return 0;
}

error C2871: 'std' : does not exist or is not a namespace
error C2653: 'std' : is not a class or namespace name

[ 本帖最后由 Sheldon 于 2010-6-26 14:44 编辑 ]

count << "I'm in main()!\n";
输出都是错的cout，头文件下添加using namespace std; 即可

#include <iostream.h>
int Add(int first, int second)
{
  cout << "In Add(),recieved " << first << "and " << second << "\n";
  return (first+second);
}

int main()
{
   cout << "I'm in main()!\n";
    int a, b, c;
    cout << "Enter two numbers: ";
    cin >> a;
    cin >> b;
    cout << "\nCalling Add();\n";
    c=Add(a,b);
    cout << "\nBack in main().\n";
    cout << "c was set to " << c;
    cout << "\nExiting...\n\n";
    return 0;
}
改成这样试下，看可不可以

#include <iostream.h>
#include<iostream>//加上这个，嘿嘿

int Add(int first, int second)
{
    std::cout << "In Add(),recieved " << first << "and " << second << "\n";
    return (first+second);
}

int main()
{
    using std::cout;
    using std::cin;
   
    count << "I'm in main()!\n";
    int a, b, c;
    cout << "Enter two numbers: ";
    cin >> a;
    cin >> b;
    cout << "\nCalling Add();\n";
    c=Add(a,b);
    cout << "\nBack in main().\n";
    cout << "c was set to " << c;
    cout << "\nExiting...\n\n";
    getchar();
    return 0;
}

这样肯定不会报错，
#include<iostream>
using namespace std;
不要用.h

#include<iostream>对了，没报错
为什么不能加.h呢？
头文件不都是.h的么？

这个应该是各个编译系统的原因吧

我想问一下，这里的getchar()有什么用？#include<iostream.h>是以前c语言的写法，以下这样也可以编译成功
#include <iostream.h>

int Add(int first, int second)
{
    cout << "In Add(),recieved " << first << "and " << second << "\n";
    return (first+second);
}

int main()
{
  
   
    cout << "I'm in main()!\n";
    int a, b, c;
    cout << "Enter two numbers: ";
    cin >> a;
    cin >> b;
    cout << "\nCalling Add();\n";
    c=Add(a,b);
    cout << "\nBack in main().\n";
    cout << "c was set to " << c;
    cout << "\nExiting...\n\n";
    //getchar();
    return 0;