C++实现分割读取txt文件以及对齐打印设置

秒速五厘米 2022-06-01 08:10 195阅读 0赞

假设现在有txt文件如下，需要将里面每一项的内容分别读取并存储，以读取文件中的FrameNo、Y\_bits以及Y\_psnr三个变量为例进行分析。

txt文件下载：[点击下载txt文件][txt]

![SouthEast][]

完整C++程序如下：

txt\_read.cpp

#include<iostream>
    #include<iomanip>
    using namespace std;
    
    void errorMsg(const char *msg) {
    	printf("error:%s\n", msg);
    #ifdef _WIN32
    	system("pause");
    #endif
    	exit(-1);
    }
    
    void read_one_frame_info(int frameNo, int *y_bits, double *y_psnr, char *fileName) {
    	int frameno = 0, qp = 0, uv_bits = 0;
    	char temp[50];
    	char errorText[50];
    	FILE *fp;
    
    	fp = fopen(fileName, "r"); 
    	if (fp == NULL) {
    		sprintf(errorText, "File %s not found", fileName);
    		errorMsg(errorText);
    	}
    
    	while (!feof(fp))
    	{
    		fscanf(fp, "%s", temp);
    		if (strcmp(temp, "FrameNo:") == 0)
    		{
    			fscanf(fp, "%s", temp); // get frame number
    			frameno = atoi(temp);
    
    			if (frameno == frameNo)
    			{
    				break;
    			}
    		}
    	}
    
    	if (feof(fp))
    	{
    		sprintf(errorText, "In function read_one_frame_info: frame number %d not found", frameNo);
    		errorMsg(errorText);
    	}
    
    
    	fscanf(fp, "%s", temp);
    	fscanf(fp, "%s", temp); // get Y_bits
    	*y_bits = atoi(temp);
    
    	fscanf(fp, "%s", temp);
    	fscanf(fp, "%s", temp); // get UV_bits
    
    	fscanf(fp, "%s", temp);
    	fscanf(fp, "%s", temp); // get QP
    
    	fscanf(fp, "%s", temp);
    	fscanf(fp, "%s", temp); // get Y_psnr
    	*y_psnr = (float)atof(temp);
    
    	fclose(fp);
    }
    
    void main()
    {
    	int frameNum = 100;
    	int *y_bit;
    	double *y_psnr;
    	y_bit = (int *)malloc(sizeof(int)*frameNum);
    	y_psnr = (double *)malloc(sizeof(double)*frameNum);
    	char *fileName = "per_frame_stat.txt";
    	for (int i = 0; i < frameNum; i++) {
    		read_one_frame_info(i, &y_bit[i], &y_psnr[i], fileName);
    		//普通输出
    		//cout << "FrameNo:" << i << "  " <<
    			//"bitRate:" << y_bit[i] << " " << " PSNR:" << y_psnr[i] << endl;
    		//对齐输出
    	    cout <<"FrameNo:"<< setw(10) << setfill(' ') << left <<i <<"  "<<
    			"bitRate:" << setw(10) << setfill(' ') << left<<y_bit[i] << " " << " PSNR:" <<y_psnr[i] << endl;
    	}
    }

注意：

cout设置对齐方式：..........<< setw(10) << setfill(' ') << left..........

对齐与非对齐方式运行结果如下，当然不同的宽度间隔可以灵活调整，也可以指定读取txt文件中的其它内容。

非对齐：

![SouthEast 1][]

对齐：

![SouthEast 2][]

[txt]: https://pan.baidu.com/s/1nxoU6fB
[SouthEast]: /images/20220601/4c291a94441f4718adfa2520300cf6b4.png
[SouthEast 1]: /images/20220601/7eab7e58784f4ffa919d713af8ca9e92.png
[SouthEast 2]: /images/20220601/45c2606e53d54a8da8ad56457ff1e75a.png