c - 如何将 "cut"命令的输出附加为循环中文件的下一列？

Question

我需要从文件中剪切一列并将其附加到另一个文件作为其下一列。它必须在循环中完成，直到满足某些条件。我正在尝试以下代码

while(limit<inFeatures){
            memset(outFile,'\0',499);
            strcpy(outFile,outputPath);
            strcat(outFile,"Top_");
            sprintf(buffer,"%d",limit);
            strcat(outFile,buffer);
            strcat(outFile,"_features-FVT.csv");
            int pos;
            for(i=0;i<limit;i++){
                pos=boolian[i]+1;
                memset(cmd,'\0',999);
                strcpy(cmd,"cut -d ',' -f");
                sprintf(buffer,"%d",pos);
                strcat(cmd,buffer);
                strcat(cmd," ");
                strcat(cmd,inputFVT);
                strcat(cmd," >> ");
                strcat(cmd,outFile);
                system(cmd);
            }
}

当我执行此操作时，结果将附加在输出文件的底部。我如何将结果附加为输出文件的下一列...？

Answer 1

感谢那些试图帮助我的人。我成功地完成了该代码。

inFile=fopen(inputFVT,"r");
        //printf("\n%s",inputFVT);//For debugging purpose
        if(inFile==NULL){
            printf("1.Cannot open the input File");exit(0);
        }

            count = 0;
            //int retVal;

            while(count<totalFeatures){
                tot_features[count]=(char *)calloc(50,sizeof(char));    
                memset(tot_features[count],'\0',49);
                int retVal = fscanf(inFile,"%[^,]",tot_features[count]);
                fflush(inFile);
                ch = fgetc(inFile);
                fflush(inFile);
                if(retVal == -1) break;
                //printf("1. %s\n", tot_features[count]); //For debugging purpose
                count = count + 1;

            }
                count = 0;
        inputFeatures=fopen(argv[2],"r");
        //printf("\n%s",argv[2]);//For debugging purpose
        if(inputFeatures==NULL){
            printf("2.Cannot open the input File");exit(0);
        }
        count = 0;
        //int retVal;

        while(count<inFeatures){
            in_features[count]=(char *)calloc(50,sizeof(char));
            memset(in_features[count],'\0',49);
            int retVal=fscanf(inputFeatures,"%[^\n]",in_features[count]);
            fflush(inputFeatures);  
            if(retVal == -1) break;
            //printf("2. %s\n", in_features[count]); //For debugging purpose
            ch = fgetc(inputFeatures);
            fflush(inputFeatures);  
            count = count + 1;
        }
            count = 0;
        for(i=0;i<inFeatures;i++){
            for(j=0;j<totalFeatures;j++){
                if((strcmp(in_features[i],tot_features[j]))==0){
                    //printf("3. \n%s %s",in_features[i],tot_features[j]);//For debugging purpose
                    boolian[i]=j+1;
                    break;
                }else{
                    boolian[i]=-1;
                }
                count++;
            }

        }

        int limit=100;
        char *buffer,temp[5];
        char outFile[500];
        //char cmd[1000];
        buffer=(char*)calloc((500+count+count),sizeof(char));
        while(limit<inFeatures){
            memset(outFile,'\0',499);
            strcpy(outFile,outputPath);
            strcat(outFile,"Top_");
            sprintf(temp,"%d",limit);
            strcat(outFile,temp);
            strcat(outFile,"_features-FVT.csv");
            strcpy(buffer,"cut -d ',' -f ");
            for(i=0;i<limit;i++){
                sort[i]=boolian[i];
            }
            quicksort(sort,0,limit-1);
            int pos;
            for(i=0;i<limit;i++){
                pos=sort[i];
                sprintf(temp,"%d,",pos);
                strcat(buffer,temp);
            }
            sprintf(temp,"%d",totalFeatures+1);
            strcat(buffer,temp);

            strcat(buffer," ");
            strcat(buffer,inputFVT);
            strcat(buffer," > ");
            strcat(buffer,outFile);
            //printf("\n%s",buffer);//Debuging code
            system(buffer);
            limit=limit+100;
        }
        strcpy(outFile,outputPath);
        strcat(outFile,"Top_");
        sprintf(temp,"%d",inFeatures);
        strcat(outFile,temp);
        strcat(outFile,"_features-FVT.csv");
        strcpy(buffer,"cut -d ',' -f");
        for(i=0;i<inFeatures;i++){
                sort[i]=boolian[i];
            }
            quicksort(sort,0,inFeatures-1);
        int pos;
            for(i=0;i<inFeatures;i++){
                pos=sort[i];
                sprintf(temp,"%d,",pos);
                strcat(buffer,temp);
            }
            sprintf(temp,"%d",totalFeatures+1);
            strcat(buffer,temp);
            strcat(buffer," ");
            strcat(buffer,inputFVT);
            strcat(buffer," > ");
            strcat(buffer,outFile);
            system(buffer);

    }