包含一個fstream的庫，然後定義一個ifstream的物件，比如下面的infile;讀取資料，方陣可以匯入二維陣列中/////////////////////////////////////////////////////////////////////#include<iostream>#include<fstream>#include<math.h>using namespace std;int main(){ int n; double density; ifstream infile("C:\\Users\\administrator\\Desktop\\M_change_V\\M_data_in.txt",ios::in); infile>>density>>n; double mass[n],V[n]; for(int i=0;i<n;i++) infile>>mass[i]; infile.close(); ofstream outfile("C:\\Users\\administrator\\Desktop\\M_change_V\\V_data_out.txt",ios::out); outfile<<"接液體積"<<endl; for(int i=0;i<n;i++) { V[i]=mass[i]/(3*density); outfile<<V[i]<<endl; } outfile.close(); cout<<"計算完成"; return 1;}

/*假設你的資料檔案是d:\ttt.txt

用迴圈把數字讀到陣列a裡面順便顯示出來 */

#include

int main()

{

double a[100];

int i=0;

FILE* fp;

if((fp=fopen("d:\\ttt.txt","r"))==0)

{

printf("無檔案!!\n");

return -1;

}

while(!feof(fp))

{

fscanf(fp,"%lf",&a[i]);

printf("%lf\n",a[i]);

i++;

}

fclose(fp);

return 0;

}