求助：C++中所有[i]下标访问均报‘subscripted value...’错误

核心报错原因 #

你遇到的subscripted value is not an array, pointer, or vector错误，根源在getData()函数的返回值处理：

• getData()声明返回int，实际只返回了0，完全没返回你创建的vector<int> weeklyScore。
• 在highScore()、lowScore()、ave()中，auto weeklyScore = getData();得到的weeklyScore是int类型（因为getData返回int），而非vector。对int使用[i]下标自然会报错——int不是数组、指针或vector类型，不支持下标访问。

修复步骤 #

1. 修正getData的返回类型和返回值
   把getData()的返回类型从int改为vector<int>，并在函数末尾返回创建好的vector：

   vector<int> getData() {
       vector<int> weeklyScore(16, 0);
       // 原有的输入逻辑保持不变
       return weeklyScore; // 新增返回vector语句
   }
   

2. 避免重复调用getData（优化体验）
   当前代码中三个分析函数各自调用getData()，会让用户重复输入三次分数，这明显不符合需求。应该在main()中只调用一次getData()，再把结果传递给三个分析函数：

   // 修改highScore，接收vector参数
   int highScore(const vector<int>& weeklyScore) {
       int high = 0;
       int ihigh = 0; // 提前声明并初始化ihigh
       for (int i = 0; i < 16; i++) {
           if (weeklyScore[i] > high) {
               high = weeklyScore[i];
               ihigh = i;
           }
       }
       cout << "The highest score is " << high << " in module " << ihigh+1 << endl;
       return 0;
   }
   
   // lowScore和ave函数做同样修改
   int lowScore(const vector<int>& weeklyScore) {
       int low = 16;
       int ilow = 0;
       for (int i = 0; i < 16; i++) {
           if (weeklyScore[i] < low) {
               low = weeklyScore[i];
               ilow = i;
           }
       }
       cout << "The lowest score is " << low << " in module " << ilow+1 << endl;
       return 0;
   }
   
   int ave(const vector<int>& weeklyScore) {
       int sum = 0;
       for (int i = 0; i < 16; i++) {
           sum += weeklyScore[i];
       }
       int average = sum / 16;
       cout << "The average score is " << average << endl; // 新增输出结果语句
       return 0;
   }
   
   // 修改main函数，只调用一次getData
   int main() {
       vector<int> scores = getData();
       highScore(scores);
       lowScore(scores);
       ave(scores);
       return 0;
   }
   

3. 修复其他小问题

   • 删掉highScore()中重复声明的int high;。
   • 给highScore()的ihigh、lowScore()的ilow添加声明和初始化，避免未定义行为。
   • 在ave()中添加输出平均分数的语句，否则计算结果不会显示。

修复后的完整代码 #

#include <iostream>
#include <string>
#include <vector>

using namespace std;

vector<int> getData() {
    vector<int> weeklyScore(16, 0);

    for (int i = 0; i < 16; i++) {
        cout << "Enter quiz score (0-15) for week " << i+1 << " : " << endl;
        cin >> weeklyScore[i];

        if (weeklyScore[i] < 0 || weeklyScore[i] > 15) {
            cout << "Please enter a valid score (0-15): " << endl;
            i--;
        }
    }

    for (int i = 0; i < 16; i++) {
        cout << "Module " << i+1 << ": " << weeklyScore[i] << endl;
    }

    return weeklyScore;
}

int highScore(const vector<int>& weeklyScore) {
    int high = 0;
    int ihigh = 0;

    for (int i = 0; i < 16; i++) {
        if (weeklyScore[i] > high) {
            high = weeklyScore[i];
            ihigh = i;
        }
    }

    cout << "The highest score is " << high << " in module " << ihigh+1 << endl;
    return 0;
}

int lowScore(const vector<int>& weeklyScore) {
    int low = 16;
    int ilow = 0;

    for (int i = 0; i < 16; i++) {
        if (weeklyScore[i] < low) {
            low = weeklyScore[i];
            ilow = i;
        }
    }

    cout << "The lowest score is " << low << " in module " << ilow+1 << endl;
    return 0;
}

int ave(const vector<int>& weeklyScore) {
    int sum = 0;

    for (int i = 0; i < 16; i++) {
        sum += weeklyScore[i];
    }

    int average = sum / 16;
    cout << "The average score is " << average << endl;
    return 0;
}

int main() {
    vector<int> scores = getData();
    highScore(scores);
    lowScore(scores);
    ave(scores);
    return 0;
}

内容的提问来源于stack exchange，提问作者Islandari