1.統計時間

#include<ctime> clock_t startTime = clock(); code(); clock_t endTime = clock(); cout << endl<< "time: " << double(endTime - startTime) / CLOCKS_PER_SEC << " s"<<endl;

2.讀取文件

#include<iostream> #include<fstream> #include<cstdlib> const int SIZE=60; int main() {using namespace std;char filename[SIZE]="information.txt";ifstream inFile;inFile.open(filename);if(!inFile.is_open()){cout<<"Could not open the file"<<filename<<endl;cout<<"Program terminating.\n";exit(EXIT_FAILURE);}double value; //1double sum=0.0;int count=0;inFile>>value; //1while(inFile.good()){++count;sum=sum+value;inFile>>value;}if(inFile.eof())cout<<"end of file reached.\n";else if(inFile.fail())cout<<"input terminated by data mismatch.\n";elsecout<<"input terminated for unknown reason.\n";if(count==0)cout<<"NO DATA PROCESSED.\n";else{cout<<"items read:"<<count<<endl;cout<<"sum:"<<sum<<endl;}inFile.close(); return 0; }

3.寫入文件

#incluede<fstream> ofstream outFile; outFile.open("carinfa.txt"); //要放入的文件名 outFile<<... //放入的信息 . . . outFile.close(); //關閉文件

4.產生0~89之間的隨機數

#include<iostream> #include<cstdlib> #include<ctime> using namespace std; int main() {double target;srand(time(0));for(int i=0;i<=20;i++){target=rand()%90;cout<<target<<endl;}return 0; }

6.傳二維數組

int show(double* A,int row,int col) {int i,j;double** B=new double*[col];for(i=0;i<row;i++){B[i]=new double[col];}for(i=0;i<row;i++){for(j=0;j<col;j++){B[i][j]=*(A+i*col+j);cout<<B[i][j]<<" ";}cout<<endl;}for(i=0;i<row;i++){delete[] B[i];}delete[] B;} //調用： show(A[0],4,7);

轉載于:https://www.cnblogs.com/qujingtongxiao/p/9862380.html

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