字符串class ==操作符不能正常工作

我试图比较我的字符串缓冲区变量中的数据到if语句中的字符串字量。由于某种原因，它适用于第一种情况，但不适用于第二或第三种情况，即使输入文件具有正确的格式(也没有空格)。问题是什么呢?

while(getline(input, check)) //calculates size of sections array and rooms array
    {
        count++;
        cout<<check<<endl;
        if(check == "-- building room_number capacity")
        {
            Section1 = true;
            pos[0] = count;
            if(pos[0] != 1)
                return 0;
        }
        else if (check == "-- ID prefix course# sect# #minutes #mtgsperweek #students")
        {
            Section1 = false;
            Section2 = true;
            pos[1] = count;
            if(blanks > 1 || blanksPos != pos[1] - 1)
                return 0;
            else
                blanks = 0;
        }
        else if (check == "-- ID days_constraint start_contraint end_constraint")
        {
            Section2 = false;
            Section3 = true;
            pos[2] = count;
            if(blanks > 1 || blanksPos != pos[2] - 1)
                return 0;
            else
                blanks = 0;
        }
        else if (Section1 && check != "-- building room_number capacity")
        {
            if(check.size() == 0)
            {
                blanks++;
                blanksPos =count; 
            }
            else
                roomsize++;
        }
        else if (Section2 && check != "-- ID prefix course# sect# #minutes #mtgsperweek #students")
        {
            if(check.size() == 0)
            {
                blanks++;
                blanksPos =count; 
            }
            else
                sectionsize++;
        }
        else if (Section3 && check != "-- ID days_constraint start_contraint end_constraint")
        {
            if(check.size() == 0)
            {
                return 0;
            }
            else
                constraintsize++;
        }   
        cout<<"R:" << roomsize << " S:" << sectionsize << " C:" << constraintsize << " blanks :" << blanks<<endl ;
    }

一些输出:欢迎来到课堂作业计划!输入输入文件:input.txt

-- building room_number capacity
R:0 S:0 C:0 blanks :0
SAL 210 30
R:1 S:0 C:0 blanks :0
OHE 100 120
R:2 S:0 C:0 blanks :0
OHE 120 50
R:3 S:0 C:0 blanks :0
R:3 S:0 C:0 blanks :1
-- ID pre course# sect# #minutes #meetingsperweek #students
R:4 S:0 C:0 blanks :1
20001 CSCI 101 01 110 2 40
R:5 S:0 C:0 blanks :1
20002 CSCI 101 02 110 2 60
R:6 S:0 C:0 blanks :1
20003 CSCI 101 03 110 2 100
R:7 S:0 C:0 blanks :1
20004 CSCI 103 01 90 2 50
R:8 S:0 C:0 blanks :1
20005 CSCI 103 02 90 2 50
R:9 S:0 C:0 blanks :1
20006 CSCI 103 03 90 2 75
R:10 S:0 C:0 blanks :1
20007 CSCI 104 01 80 2 50
R:11 S:0 C:0 blanks :1
20008 CSCI 104 02 80 2 50
R:12 S:0 C:0 blanks :1
20009 CSCI 109 01 90 1 25
R:13 S:0 C:0 blanks :1
20010 CSCI 109 02 90 1 25
R:14 S:0 C:0 blanks :1
20011 CSCI 109 03 90 1 25
R:15 S:0 C:0 blanks :1
20012 CSCI 109 04 90 1 25
R:16 S:0 C:0 blanks :1
R:16 S:0 C:0 blanks :2
-- ID days_constraint start_contraint end_constraint

正如您所看到的，它没有检测到"——ID pre course# sect# #minutes #meetingsperweek #students"，尽管检查输出的结果与测试用例相同。什么好主意吗?