map unclared:首先在函数错误中使用

Question

#include<stdio.h>
#include<map>

int main()
{
    int cases, i, j, act, answer, min_ind, min_val, temp1, temp2;
    scanf("%d",&cases);

    for(i=0; i<cases; i++)
    {
        answer = 0;
        scanf("%d", &act);
        map<int, int> mymap;

        for(j=0; j<act; j++)
        {
            scanf("%d",&temp1);
            scanf("%d",&temp2);
            mymap[temp2] = temp1;
        }

        map<int,int>::iterator it = mymap.begin();
        temp1 = it->second;

        while(mymap.size() != 0)
        {
            it = mymap.begin();
            if(it->second < temp1)
            {
                mymap.erase(it);
                continue;
            }

            answer++;
            temp1 = it->first;
            mymap.erase(mymap.begin());

            if(mymap.size() != 0)
            {
                it = mymap.begin();
                while(it->second < temp1)
                {
                    mymap.erase(it);
                    it = mymap.begin();
                }
            }
        }

        printf("%d\n",answer);
    }

    return 0;
}

我按照C++的STL包含了映射头,但仍然没有编译并给出编译错误.我试过包含map.h头文件,但仍然得到相同的错误

错误:

prog.cpp: In function 'int main()':
prog.cpp:13: error: 'map' was not declared in this scope
prog.cpp:13: error: expected primary-expression before 'int'
prog.cpp:13: error: expected `;' before 'int'
prog.cpp:19: error: 'mymap' was not declared in this scope
prog.cpp:22: error: expected primary-expression before 'int'
prog.cpp:22: error: expected `;' before 'int'

看看我的代码,并帮助我解决这个问题.在此先感谢您的帮助.

Answer 1

您需要使用std命名空间.

无论是键入std::map而不是在开头map使用using std::map;.

或者如果你真的很懒,你可以键入using namespace std;以使用所有标准函数和类型.但要注意姓名冲突.