C++ 文件读写示例

输入文件被看作输入流

输出文件被看作输出流

进行文件操作需包含头文件fstream

//this program repeatedly reads an income from//the file incom.in until end-of file.//Income under 6000 greenbacks is taxed at 30 percent,//and income greater than or equal to 6000//greenbacks is taxed at 60 percent.//After reading each income, the program prints the //income and tax.#include<fstream>using namespace std;const int cutoff=6000;const float rate1=0.3;const float rate2=0.6;int main(){ifstream infile;ofstream outfile;int income, tax;infile.open("income.in");outfile.open("tax.out");while(infile>>income){if(income < cutoff)tax = rate1 * income;elsetax = rate2 * income;outfile<<"tax= "<<tax<<endl;}infile.close();outfile.close();return 0;}