C++(使用文件数据通过函数进行计算）

C++ ( using file data to make calculation through functions)

本文关键字：函数 计算 文件 数据 C++      更新时间：2023-10-16
在一个

函数中读取文件后如何使用该文件，并在另一个函数中进行计算？

这是我尝试制作的代码..

void readFile(ifstream&); //file reading 
void DisplayAdd(ifstream& somefile);  //here what i don't understand do i use void or int !  
//and how is it going to use the data from the file !!

int main()
{
ifstream inputfile;
inputfile.open("numbers.txt");
readFile(inputfile);         //calling function to make reading file
DisplayAdd(inputfile);      //calling function to make addition
}
inputfile.close(); //closing file
return 0;
}
void readFile(ifstream& somefile) //reading data from file ..
{
double num1,num2,num3,num4,num5;
while(somefile>>num1>>num2>>num3>>num4>>num5)
    cout<<num1<<endl<<num2<<endl<<num3<<endl<<num4<<endl<<num5<<endl;
}
void DisplayAdd(ifstream& somefile) //how to make the calculation here is it like this !
{cout<<num1+num2+num3+num4+num5;
}

No.

#include <iostream>
#include <fstream> // you include HEADER needed for files using
using namespace std;
ifstream f("date.txt"); // you DECLARE the FILE data
int returnNumber(); // you PROTOTYPE your function (I guess you know about this)
int nr, a = 10, b = 10; // you declare your GLOBAL variables

int main()
{
    cout << returnNumber(); // you SHOW the number you got after calculation on screen
    return 0;
}

int returnNumber(){ // here's the function; int type because you return a integer value
    f >> nr; // you READ the VALUE from the file
    nr = nr + a + b; // you make a CALCULATION inside function
    return nr; // you RETURN the number
}
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