类和对象-4

一个考试成绩结果统计的小程序，共3个文件

Analysis.h：头文件声明

// Analysis.h

// Definition of class Analysis that analyzes examination results.

// Member-function is defined in Analysis.cpp

// Analysis class definition

class Analysis

{

public:

    // process 10 students‘ examination results

    void processExamResults();

};    // end class Analysis

Analysis.cpp：统计分析的具体实现

// Analysis.cpp

// Member-functions for class Analysis that

// analyzes examination results

#include <iostream>

using std::cout;

using std::cin;

using std::endl;
// include definition of class Analysis from Analysis.h

#include "Analysis.h"
// process the examination results of 10 students

void Analysis::processExamResults()

{

    // initializing variables in declaration

    int passes = 0;        // number of passes

    int failures = 0;    // number of failures

    int studentCounter = 1;    // student counter

    int result;            // one exam result ( 1 = pass, 2 = fail )
// process 10 students using counter-controlled loop

    while (studentCounter<=10)

    {

        // prompt user for input and obtain value from user

        cout << "Enter result ( 1 = pass, 2 = fail )";

        cin >> result;    // input result
// if...else nested in while

        if (result == 1)    // if result is 1

        {

            passes++;        // increment passes,

        }

        else                // if result is not 1, so

        {

            failures++;        // increment failures

        }
studentCounter++;    // increment studentCounter to loop eventually terminates

    }    // end while
// termination phase: display number of passes and failures

    cout << "Passed: " << passes << "\nFailures: " << failures << endl;
// determine whether more than 8 students passes

    if( passes >= 8 )

        cout << "Raise tuition!\n";

}    // end function processExamResults

test.cpp：测试文件

// test.cpp

// Test program for class Analysis

#include "Analysis.h"

int main()

{

    Analysis application;        // create Analysis object

    application.processExamResults();    // call function to process results
return 0;    // indicate successful termination

}    // end main

良好的编程习惯

与二元运算符不同，一元的自增和自减运算符应该紧邻其操作数，中间不能有任何数据

常见的编程错误

企图用表达式（不是一个可修改变量的名字和引用），例如++（x+1），作为自增或自减运算符操作将是一个语法错误