创建一个字符串函数返回一个月

Question

这里是我现在拥有的代码。就目前而言，它可以完成它所需的一切，以返回必要的相应值。但是，我缺少的一件事是返回与温度相关的索引号相对应的月份的函数。

#include <iostream> 
#include <fstream> 
#include <iomanip> 
#include <string> 
#include <cstdlib> 

using namespace std; 

const int NUM_COLS = 2; 
const int NUM_ROWS = 12; 

void getData(ifstream& tempFile, double temps[][NUM_COLS]); 
double averageHigh(double temps[][NUM_COLS], int NUM_ROWS); 
double averageLow(double temps[][NUM_COLS], int NUM_ROWS); 
double indexHighTemp(double temps[][NUM_COLS], int NUM_ROWS); 
double indexLowTemp(double temps[][NUM_COLS], int NUM_ROWS); 
string monthForTemp(double temps[][NUM_COLS], int NUM_ROWS); 

/* 
* 
*/ 
int main(int argc, char** argv) 
{ 
    ifstream tempFile; 
    double temps[NUM_ROWS][NUM_COLS] = {0.0}; 
    tempFile.open("Ch8_ex9Data.txt"); 

    if (!tempFile) 
    { 
     cout << "File does not exist, contact system admin" << endl; 
     return 1; 
    } 
    getData (tempFile, temps); 
    double highAverage = averageHigh(temps, NUM_ROWS); 
    cout << "Average high is: " << highAverage << endl; 

    double lowAverage = averageLow(temps, NUM_ROWS); 
    cout << "Average low is: " << lowAverage << endl; 

    int indexHiTemp = indexHighTemp(temps, NUM_ROWS); 
    cout << "High temp index is: " << indexHiTemp 
     << " which is " << temps[indexHiTemp][0] 
     << " degrees F" << endl; 

    int indexLoTemp = indexLowTemp(temps, NUM_ROWS); 
    cout << "Low temp index is: " << indexLoTemp 
     << " which is " << temps[indexLoTemp][1] 
     << " degrees F" << endl; 
    return 0; 



} 

void getData(ifstream& tempFile, double temps[][NUM_COLS]) 
{ 
    cout << fixed << showpoint << setprecision(1); 
    double hiTemp, loTemp; 

    tempFile >> hiTemp >> loTemp; 

    int rowIndex = 0; 

    while(tempFile) 
    { 
     temps[rowIndex][0] = hiTemp; 
     temps[rowIndex][1] = loTemp; 
     rowIndex++; 
     tempFile >> hiTemp >> loTemp; 
    } 
} 

double averageHigh(double temps[][NUM_COLS], int NUM_ROWS) 
{ 
    double avgHigh = 0.0; 
    double sum = 0.0; 
    int i; 

    for (i = 0; i < NUM_ROWS; i++) 
    { 
     sum += temps[i][0]; 
     //cout << temps[i][0] << endl; 
    } 
    avgHigh = sum/NUM_ROWS; 
    return avgHigh; 
} 

double averageLow(double temps[][NUM_COLS], int NUM_ROWS) 
{ 
    double avgLow = 0.0; 
    double sum = 0.0; 
    int i; 

    for (i = 0; i < NUM_ROWS; i++) 
    { 
     sum += temps[i][1]; 
     //cout << temps[i][1] << endl; 
    } 
    avgLow = sum/NUM_ROWS; 
    return avgLow; 
} 

double indexHighTemp(double temps[][NUM_COLS], int NUM_ROWS) 
{ 
    cout << fixed << showpoint << setprecision(1); 
    double index = 0.0; 
    double maxHighTemp = 0.0; 
    for (int i = 0; i < NUM_ROWS; i++) 
    { 
     if (temps[i][0] > maxHighTemp) 
     { 
      maxHighTemp = temps[i][0]; 
      index = i; 
     } 
    } 
    return index; 
} 

double indexLowTemp(double temps[][NUM_COLS], int NUM_ROWS) 
{ 
    cout << fixed << showpoint << setprecision(1); 
    double index = 0.0; 
    double maxLowTemp = 0.0; 
    string month = " "; 
    for (int i = 0; i < NUM_ROWS; i++) 
    { 
     if (temps[i][0] < maxLowTemp) 
     { 
      maxLowTemp = temps[i][1]; 
      index = i; 
     } 

    } 
    return index, month; 
} 

string monthForTemp(double temps[][NUM_COLS], NUM_ROWS) 
{ 
    string month = " "; 
    switch (index) 
     { 
      case 1 : 
       month = "January"; 
       break; 
      case 2 : 
       month = "February"; 
       break; 
      case 3 : 
       month = "March"; 
       break; 
      case 4 : 
       month = "April"; 
       break; 
      case 5 : 
       month = "May"; 
       break; 
      case 6 : 
       month = "June"; 
       break; 
      case 7 : 
       month = "July"; 
       break; 
      case 8 : 
       month = "August"; 
       break; 
      case 9 : 
       month = "September"; 
       break; 
      case 10 : 
       month = "October"; 
       break; 
      case 11 : 
       month = "November"; 
       break; 
      case 12 : 
       month = "December"; 
       break; 
     } 

    return month; 
} 

我需要的行和列值传递给字符串函数，但我不能完全似乎得到它的权利。任何指针？

谢谢。

Answer 1

string monthForTemp(double temps[][NUM_COLS], NUM_ROWS) 

被错误地声明，无法执行其任务。它应该是这个样子

string monthForTemp(int index) 

但要做到这一点，indexHighTemp和指数返回功能的其余部分需要更改为类似

int indexHighTemp(double temps[][NUM_COLS], int NUM_ROWS) //returns int 
{ 
    cout << fixed << showpoint << setprecision(1); 
    int index = 0; // index is int 
    double maxHighTemp = 0.0; 
    for (int i = 0; i < NUM_ROWS; i++) 
    { 
     if (temps[i][0] > maxHighTemp) 
     { 
      maxHighTemp = temps[i][0]; 
      index = i; 
     } 
    } 
    return index; 
} 

因为数组不能使用double S作为指标。你不能从3.1459获得数组中的项目。此外，因为i是int，所以index就是double。最好它是一个浮点表示的整数，最坏的情况下（这里没有问题，因为数字很小），它被floating point imprecision损坏。

这里是一个伟大的pplace到Head into X-Y territory，并提出了完全不同的解决方案：

与阵列替换monthForTemp功能。例如：

std::string monthForTemp[] = 
{ 
    "January", 
    "February", 
    "March", 
    // rest of months go here 
}; 

可作为

cout << "High temp month is: " << monthForTemp[indexHiTemp] 
    << " which is " << temps[indexHiTemp][0] 
    << " degrees F" << endl; 

假设indexHighTemp已被修改为返回int如上建议。