C语言处理CSV数据

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以下代码为博客

《Python的并行求和例子》：

http://www.cnblogs.com/instant7/p/4312786.html

中并行python代码的C语言重写版。

用C来跑一遍单线程也只需要50秒，比python 开4进程的实现要快6倍多，CPU占用率也只用python的1/4。

看来计算密集型应用还是需要用这些不顺手的老古董来弄的：）

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <fstream>
#include <time.h>using namespace std;char *trim(char *str)
{
char *p = str;
while (*p == ' ' || *p == '\t' || *p == '\r' || *p == '\n')
p ++;
str = p;
p = str + strlen(str) - ;
while (*p == ' ' || *p == '\t' || *p == '\r' || *p == '\n')
-- p;
*(p + ) = '\0';
return str;
}int main(){
cout<<"start time: ";
system("Echo %Date% %Time%");
FILE *fexp, *fpred;
fexp = fopen("D:\\kaggle\\rain\\train_exp.csv", "r");
fpred = fopen("D:\\kaggle\\rain\\trainChangeTimePeriod.csv","r"); char expLine[];
char predLine[]; fgets(expLine, sizeof(expLine), fexp);
fgets(predLine, sizeof(predLine), fpred); double squareErrorSum = ;
int rowCnt = ;
while(fgets(expLine, sizeof(expLine), fexp)) {
//printf("%s", expLine);
fgets(predLine, sizeof(predLine), fpred);
//printf("%s", predLine); char *save_ptr;
char *expId = trim(strtok_s(expLine, ",", &save_ptr));
if (expId == NULL) {
return -;
}
char *exp = trim(strtok_s(NULL, ",", &save_ptr));
double expVal = atof(exp);
//printf("%s\t%s\n", expId, exp); char *predId = trim(strtok_s(predLine, ",", &save_ptr));
//printf("%s\n", predId);
double prob[];
rowCnt += ;
if (rowCnt % == )
cout << rowCnt << " finished"<<endl;
for (int i = ; i < ; i++){
char *temp = trim(strtok_s(NULL, ",", &save_ptr));
prob[i] = atof(temp);
squareErrorSum += pow((prob[i]-(i>=expVal)),);
//cout<<squareErrorSum<<endl;
}
}
double score = squareErrorSum / ( * rowCnt);
cout<<"Score: "<<score<<endl;
cout<<"end time: ";
system("Echo %Date% %Time%");
system("pause");
return ;
}