图上的表格就是要读取的数据，程序如下，主要是我不太清楚数据文件格式是什么，程序应该没错
#include
#include

include"stdlib.h"

#include"stdio.h"
#include
#include
using namespace std;
#include"time.h"
#include"math.h"
float demand[101],tlead[101],qua,ord;
float maxt,CLOCK;
float teout,test,iest,est,arr,costo,costs;
void ss1();
void ss2();
void main()
{float tcosts,tcost,ax,tcosto;
srand(time(NULL));
cout<<"输入！\n";
cout<<"初始库存是：";cin>>iest;
cout<<"单位保管费是：";cin>>costs;
cout<<"缺料损失费是：";
cin>>costo;
LOOP:cout<<"订货量是：";cin>>qua;
if(qua>0){cout<<"临界库存量是：";cin>>ord;
cout<<"最大仿真时间是：";cin>>maxt;est=iest;
arr=999999;
teout=0.00;
test=0.00;
cout<<"订货量是："< cout cout cout cout cout getchar();
cout cout for(CLOCK=1;CLOCK {ss2();}
tcosto=costo*teout;tcosts=costs*test;tcost=tcosto+tcosts;
cout cout cout ax=tcost/maxt;
cout goto LOOP;}}
void ss1()
{ FILE*fp;
int i,is,ie,id;
fp=fopen("demand.txt","r");
while(!feof(fp))
{fscanf(fp,"%d%d%d",&is,&ie,&id);
cout getchar();
for(i=is;i {demand[i]=id;}}
fclose(fp);
fp=fopen("days.txt","r");
while(!feof(fp))
{fscanf(fp,"%d%d%d",&is,&ie,&id);
cout getchar();
for(i=is;i {tlead[i]=id;}}
fclose(fp);
return;}
void ss2()
{int nr;
float bst,bdem,eout,xi;
if(CLOCK>=arr)
{bst=est+qua;
arr=999999;}
else
bst=est;
nr=rand()%100;
nr=nr+1;
bdem=demand[nr];
if(bst>bdem)
{eout=0.00;
est=bst-bdem;}
else
{eout=bdem-bst;
est=0.00;}
teout=teout+eout;
test=test+est;
float p;
p=0.00;
if(est<=ord)
{if(arr>=999999)
{nr=rand()%100;
nr=nr+1;
p=tlead[nr];
arr=p+CLOCK;}}
if(CLOCK<=20)
{xi=costo*eout+costs*est;
cout<<setw(8)<<CLOCK
<<setw(8)<<bst<<setw(8)<<bdem;
cout<<setw(8)<<est<<setw(8)<<eout<<setw(8)<<p<<setw(10)<<arr<<setw(10)<<xi<<endl;}return;}

楼主fopen打开文件失败？（检查文件名，当前目录一般是工程目录，而不是EXE所在目录，写上完整路径试试）
还是说能打开的，只是代码有问题（建议单步调试）
单步调试和设断点调试（VS IDE中编译连接通过以后，按F10或F11键单步执行，按Shift+F11退出当前函数；在某行按F9设断点后按F5执行停在该断点处。）是程序员必须掌握的技能之一。
帮楼主整理了下格式：

 #include<iostream>
#include<cmath>
# include"stdlib.h"
#include"stdio.h"
#include<iostream>
#include<iomanip>
using namespace std;
#include"time.h"
#include"math.h"
float demand[101],tlead[101],qua,ord;
float maxt,CLOCK;
float teout,test,iest,est,arr,costo,costs;
void ss1();
void ss2();
void main()
{
    float tcosts,tcost,ax,tcosto;
    srand(time(NULL));
    cout<<"输入！\n";
    cout<<"初始库存是：";cin>>iest;
    cout<<"单位保管费是：";cin>>costs;
    cout<<"缺料损失费是：";
    cin>>costo;
LOOP:cout<<"订货量是：";
    cin>>qua;
    if(qua>0){
        cout<<"临界库存量是：";
        cin>>ord;
        cout<<"最大仿真时间是：";cin>>maxt;est=iest;
        arr=999999;
        teout=0.00;
        test=0.00;
        cout<<"订货量是："<<qua<<endl;
        cout<<"临界库存量是："<<ord<<endl;
        cout<<"最大仿真时间是："<<maxt<<endl;
        cout<<"初始库存是："<<est<<endl;
        cout<<"缺料损失费是："<<costo<<endl;
        cout<<"单位保管费是："<<costs<<endl;
        getchar();
        cout<<"      时钟   可供数  需求库存";
        cout<<"  缺料数       到货天数   到货日期   每日费用"<<endl;
        for(CLOCK=1;CLOCK<=maxt;CLOCK++)
        {
            ss2();
        }
        tcosto=costo*teout;tcosts=costs*test;tcost=tcosto+tcosts;
        cout<<"总缺货费是："<<endl;
        cout<<"总保管费是："<<endl;
        cout<<"总费用是："<<tcost<<endl;
        ax=tcost/maxt;
        cout<<"日平均费用是："<<ax<<endl;
        goto LOOP;}}
void ss1()
{  
    FILE*fp;
    int i,is,ie,id;
    fp=fopen("demand.txt","r");
    while(!feof(fp))
    {
        fscanf(fp,"%d%d%d",&is,&ie,&id);
        cout<<is<<""<<ie<<""<<id<<endl;
        getchar();
        for(i=is;i<=ie;i++)
        {
            demand[i]=id;}}
    fclose(fp);
    fp=fopen("days.txt","r");
    while(!feof(fp))
    {
        fscanf(fp,"%d%d%d",&is,&ie,&id);
        cout<<is<<""<<ie<<""<<id<<endl;
        getchar();
        for(i=is;i<=ie;i++)
        {
            tlead[i]=id;}}
    fclose(fp);
    return;
}
void ss2()
{
    int nr;
    float bst,bdem,eout,xi;
    if(CLOCK>=arr)
    {
        bst=est+qua;
        arr=999999;}
    else
        bst=est;
    nr=rand()%100;
    nr=nr+1;
    bdem=demand[nr];
    if(bst>bdem)
    {
        eout=0.00;
        est=bst-bdem;}
    else
    {
        eout=bdem-bst;
        est=0.00;}
    teout=teout+eout;
    test=test+est;
    float p;
    p=0.00;
    if(est<=ord)
    {if(arr>=999999)
    {nr=rand()%100;
    nr=nr+1;
    p=tlead[nr];
    arr=p+CLOCK;}}
    if(CLOCK<=20)
    {
        xi=costo*eout+costs*est;
        cout<<setw(8)<<CLOCK
            <<setw(8)<<bst<<setw(8)<<bdem;
        cout<<setw(8)<<est<<setw(8)<<eout<<setw(8)<<p<<setw(10)<<arr<<setw(10)<<xi<<endl;
    }
    return;
}