c++精解和程序设计.doc

* 清单2-4 */ File: coins.cpp/ Determines the values of a coin collection#include #include using namespace std;int main()string name;/ input: nieces first nameint pennies;/ input: count of penniesint nickels;/ input: count of nickelsint dollars;/ output: value of coins in dollarsint change;/ output: value of coins in centsint totalCents; / total cents represented/ Read in your nieces first name.cout name;/ Read in the count of nickels and pennies.cout nickels;cout pennies;/ Compute the total value in cents.totalCents = 5 * nickels + pennies;/ Find the value in dollars and change.dollars = totalCents / 100;change = totalCents % 100;/ Display the value in dollars and changecout Good work name ! endl;cout You collection is worth dollars dollars and change cents. endl; return 0;*将英里转化为千米的程序的批处理版本*/ File: milesBatch.cpp/ Converts distance in miles to kilometers.#include using namespace std;int main()const float KM_PER_MILE = 1.609;/ 1.609 km in a milefloat miles,/ input: distance in miles kms;/ output: distance in kilometers/ Get the distance in miles.cin miles;cout The distance in miles is miles endl;/ Convert the distance to kilometers.kms = KM_PER_MILE * miles;/ Display the distance in kilometers.cout The distance in kilometers is kms endl;return 0;*string操作说明*/ File: stringOperations.cpp/ Illustrates string operations#include #include using namespace std;int main()string firstName, lastName;/ inputs - first and last names string wholeName;/ inputs - whole namestring greeting = Hello ;/ output - a greeting string/ Read first and last names.cout firstName;cout lastName;/ Join names in whole namewholeName = firstName + + lastName;/ Display results cout greeting wholeName ! endl;cout You have (wholeName.length() - 1 ) letter in your name. endl;/ Display initialscout Your initials are firstName.at(0) lastName.at(0) endl;return 0;*/ File: testScale.cpp/ Tests function scale #include #include using namespace std;/ Function prototype float scale(float, int);int main()float num1;int num2;/ Get value from num1 and num2cout num1;cout num2;/ Call scale and display the result.cout Result of call to function scale is scale(num1, num2)/ actual arguments endl; return 0;float scale(float x, int n) / formal argumentsfloat scaleFactor;scaleFactor = pow(10, n);return ( x * scaleFactor);清单6-1 测试函数moneyToNumberString/ 此函数具有删除出现在它的字符串中的美元符号和所有逗号的功能/ File: moneyToNumberTest.cpp/ Tests function moneyToNumberString #include #include using namespace std; / Function prototypevoid moneyToNumberString(string&);int main()string mString;/ input - a mmoney string cout mString;moneyToNumberString(mString);cout The dollar amount as a number is mString = 0 & posComma moneyString.length() / Is posComma valid ?moneyString.erase(posComma, 1);/ Remove ,posComma = moneyString.find(,);/ Find next ,/ endmoneyToNumberString清单6-2 计算求和与平均值的函数/ File: computeSumAve.cpp/ Computes and print the sum and average of a collection of date.#include using namespace std;/ Function used ./ Computes sum of datefloat computeSum(int);float computeAve(int, float);void printSumAve(int, float, float);int main()int numItems;/ input - number of items to be addedfloat sum;/ output - accumulated sum of datafloat average;/ output - average of the data / Read the number of items to process.cout numItems;/ Compute the sum of the data.sum = computeSum(numItems);/ Compute the average of the data.average = computeAve(numItems, sum);/ Print the sum and the average.printSumAve(numItems, sum, average);return 0;/ Computes the sum of data.float computeSum(int numItems)float item;float sum;/ Read each data item and accumulate it in sum.sum = 0.0;for(int count = 0; count numItems; count+)cout item;sum += item;return sum; / end computeSum/ Computes average of datafloat computeAve(int numItems, float sum)/ Compute the average of the data.if (numItems 1)/ test for invalid inputcout Invalid values for numItems = numItems endl;cout Average not computed. 0)cout The number of items is numItems endl;cout The sum of the data is sum endl;cout The average of the data is average endl;elsecout Invalid number of items = numItems endl;cout Sum and average are not defined. endl;cout No prints done. Execution terminated. endl; / end if / end printSumAve清单6-2 一般求和与平均值问题的样例运行结果Enter the number of items to process: 3Enter a number to be added: 5Enter a number to be added: 6Enter a number to be added: 17The number of items is 3The sum of the data is 28The average of the data is 9.33333Press any key to continue清单6-3 对3 个数据进行排序的函数/ File: sort3Numbers.cpp/ Read three numbers and sorts them in ascending order.#include using namespace std;/ Function used ./ Sorts a pair of numbersvoid order(float& ,float&);int main()float num1, num2, num3;/ user input - numbers to sort/ Read 3 numbers.cout num1 num2 num3;/ Sort them.order(num1, num2);/ order data in num1 & num2 order(num1, num3);/ order data in num1 & num3order(num2, num3);/ order data in num2 & num3/ Display results.cout The three numbers in order are: endl;cout num1 num2 num3 y)temp = x;x = y;y = temp; / end order 清单 6-4 测试getFrac函数_/ 此函数有用户输入一个简分数,并通过两个int类型的输出参数返回分子和分母/ File: testGetFrac.cpp/ Test function getFrac#include using namespace std;void getFrac(int& , int&);int main()int num, denom;/ intput - fraction numerator and denominatorcout Enter a common fraction as 2 integers separated by a slash: ;getFrac(num, denom);cout Fraction is num / denom numerator slash denominator; / end order 清单6-5 计算和与平均值的函数/ File: computeSumAve.cpp/ Test function computeSumAve#include using namespace std;void computeSumAve(float, float, float&, float&);int main()float x, y, sum, mean;cout x y;/ Compute the sum and the average of x and ycomputeSumAve(x, y, sum, mean);/ Display resultscout Sum is sum endl;cout Average is mean endl;return 0;void computeSumAve(float num1, float num2, float& sum, float& average)sum = num1 + num2;average = sum / 2.0; / end order 清单7-1 ASCII码排列顺序程序实例/ File: collate.cpp/ Display part of the character collating sequence#include using namespace std;int main()const MIN = 32;/ smallest numeric code const MAX = 126;/ largest numeric codechar nextChar;/ output - character form of next code/ Display sequence of characters.for(int nextCode = MIN; nextCode = MAX; nextCode+)nextChar = char(nextCode); cout nextChar; if (nextChar = Z)cout endl;cout endl;return 0;清单 7-2 digitToNumber函数#include using namespace std;digitToNumber(char);int main()char ch1;cout ch1;cout the number to the digit is: digitToNumber(ch1);cout endl;return 0;int digitToNumber(char ch)if(isdigit(ch)return (int(ch) - int(0);elsereturn -1;清单8-2 处理流中的各个字符_ / File : countChars.cpp/ Counts number of characters in a line and lines in a stream#include #include using namespace std;#define ENDFILE CRRL-Zint main()const char NWLN = n;char next;/ next character in current lineint charCount;/ number of character in current line int lineCount;/ keeps track of number of lines in filelineCount = 0;cout Enter a line or press ENDFILE : ;cin.get(next);/ get first char of new linewhile(!cin.eof()charCount = 0;/ initialize character count for new linewhile(next != NWLN)cout.put(next);charCount+;/ Increment character count.cin.get(next);/ Get next character. / end inner while cout.put(NWLN);lineCount+;cout Number of characters in line lineCount is charCount endl;cout Enter a line or press ENDFILE : ;cin.get(next);/ Get next character. / end outer while cout endl endl Number of lines processed is lineCount endl;return 0;清单8-3 拷贝文件/ File : copyFile.cpp/ Copies file InData.txt to file OutData.txt#include #include / for external file streams#include / for definition of EXIT_FAILUREusing namespace std;/ Associate stream object with external file names#define inFile D:My Documentsnspk1.txt/ directory name for inFile #define outFile D:My DocumentsOutData.txt/ directory name for Outfile / Function used ./ Copies one line of text int copyLine(ifstream&, ofstream&);int main()int lineCount;/ output: number of lines processed ifstream ins;/ ins is an input stream ofstream outs;/ outs is an output stream/ Open input and output file, exit on any errorins.open(inFile);/ connnect ins to file inFileif(ins.fail()cerr * ERROR: Cannot open inFile for input. endl;return EXIT_FAILURE;/ failure returnouts.open(outFile);/ connect outs to file outFile if(outs.fail()cerr * ERROR: Cannot open outFile for output. endl;return EXIT_FAILURE;/ failure return / Copy each character from inData to outData.lineCount = 0;while(!ins.eof()if(copyLine(ins,outs) != 0)lineCount+;/ Display a message on the screen.cout Input file copied to output file. endl;cout lineCount lines copied. endl;ins.close();/ close input file streamouts.close();/ close poutput file streamreturn 0; / Copy one line of text from one file to another int copyLine(ifstream& ins, ofstream& outs)const char NWLN = n; / newline character char nextCh;/ inout: character buffer int charCount = 0;/ Copy all data character from stream ins to stream outs.ins.get(nextCh);while(nextCh != NWLN) & !ins.eof()outs.put(nextCh);charCount+;ins.get(nextCh); / end while/ If last character read was NWLN write it to outs.if(!ins.eof()outs.put(NWLN);charCount+;return charCount; / end copyLine 可以使用下面的代码上面主函数的循环，在头文件中加入#include string line;lineCount = 0;getline(ins, line);while(line.length() != 0)lineCount+;outs line endl;getline(ins, line);清单8-4 计算员工工资及总工资_/ File : payrollFile.cpp/ Creates a company employee payroll file/ Computes total company payroll amount#include #include / required for file streams#include / for definition of EXIT_FAILURE#include using namespace std;/ Associate stream object with external file names#define inFile D:My DocumentsEmpFile.txt/ directory name for inFile #define outFile D:My DocumentsSalary.txt/ directory name for Outfile / Function used ./ Processs all employees and compute total float processEmp(ifstream&, ofstream&);int main()ifstream eds;/ input: employee data stream ofstream pds;/ output: payroll data streamfloat totalPayroll;/ output: total payroll/ Prepare files.eds.open(inFile);/ connnect ins to file inFileif(eds.fail()cerr * ERROR: Cannot open inFile for input. endl;return EXIT_FAILURE;/ failure returnpds.open(outFile);/ connect outs to file outFile if(pds.fail()cerr * ERROR: Cannot open outFile for output. endl;eds.close();return EXIT_FAILURE;/ failure return / Process all employees and compute total payrol.totalPayroll = processEmp(eds, pds);/ Display resultcout Total payroll is $ totalPayroll firstName lastName hours rate;while(!eds.eof()salary = hours * rate;pds firstName lastName salary firstName lastName hours rate; / end while return payroll; / end processEmp程序运行结果：Salary.txt文件中的内容：Jim Baxter 257.375Adrian cCybriwsky 260Ayisha Mertens 160Total payroll is $677.375清单8-5 使用函数getline和ignore 读取并处理这个文件的所有记录_/ File : payrollFile.cpp/ Creates a company employee payroll file/ Computes total company payroll amount#include #include / required for file streams#include / for definition of EXIT_FAILURE#include using namespace std;/ Associate stream object with external file names#define inFile D:My DocumentsEmpFile.txt/ directory name for inFile #define outFile D:My DocumentsSalary.txt/ directory name for Outfile / Function used ./ Processs all employees and compute total float processEmp(ifstream&, ofstream&);int main()ifstream eds;/ input: employee data stream ofstream pds;/ output: payroll data streamfloat payroll;float hours;float rate;float salary;string name;/ Prepare files.eds.open(inFile);/ connnect ins to file inFileif(eds.fail()cerr * ERROR: Cannot open inFile for input. endl;return EXIT_FAILURE;/ failure returnpds.open(outFile);/ connect outs to file outFile if(pds.fail()cerr * ERROR: Cannot open outFile for output. hours rate;salary = hours * rate;pds name salary endl; payroll += salary;eds.ignore(