比较fscanf 和getline读取文件效率

一时失言乱红尘 2023-06-22 04:24 14阅读 0赞

#include <iostream>
    #include <fstream>
    #include <vector>
    #include <string>
    #include <ctime>
    #include<cstring>
    using namespace std;
    
    class data{
    
    public:
        int src;
        int dest;
        long weight;
    };//行的类定义
    
    int main()
    {
        vector<data> incsv;
        data intp;
      
     //第一种方法读取文件
        FILE *fp;
        clock_t begin=clock();
        fp=fopen("graph.txt","r");//文件路径
        while(1){
            fscanf(fp,"%d %d %ld",&intp.src,&intp.dest,&intp.weight);
            incsv.push_back(intp);
            if (feof(fp))break;
        }
        fclose(fp);
        cout<<"time="<<double(clock()-begin)/CLOCKS_PER_SEC<<endl;
        cout<<incsv.size()<<endl;
    	incsv.clear();
    
        //第二种方法读取文件
        begin=clock();
        ifstream in("graph.txt");
        
    	char buf[100];
    	const char* d=" ";
    	long m=0;
    	long a[3];
    	while (in.getline(buf,100)) // 
    	{ 
    		m++;
    		char* p=strtok(buf,d);
    		int i=0;
    		while (p){			
    			a[i]=atol(p); // 
    			p=strtok(NULL,d);
    			//cout<<a[i]<<" ";
    			//cout<<p<<endl;
    			i=i+1;		
    		}
    		delete p;
    		intp.src=(int)a[0];
    		intp.dest=(int)a[1];
    		intp.weight=(long)a[2];
    		incsv.push_back(intp);
    	}
        cout<<"time="<<double(clock()-begin)/CLOCKS_PER_SEC<<endl;
        cout<<incsv.size()<<endl;
    	incsv.clear();
       
    //system("pause");*/
    return 0;
    }

![20191213220815646.png][]

结果是使用getline更快一些，600万条的数据使用0.9秒

[20191213220815646.png]: https://img-blog.csdnimg.cn/20191213220815646.png