[lsd]

Поковырялся в загашниках.
нашел прогу.Здесь представлено:Операторы сравнения и логические операторы,Побитовые операторы,Условные операторы,Оператор switch,Операторы перехода,Операторы цикла,Массивы,Запись результатов .Мб кому то поможет...

#include<iostream.h>
#include<math.h>
#include<stdio.h>
void kwad()

{
	{
    float a,b,c,d;
    double x1,x2;
    char key;
    do
    {
    cout<<"vvedite a=";
    cin>>a;
    cout<<"vvedite b=";
    cin>>b;
    cout<<"vvedite c=";
    cin>>c;
        d=b*b-4*a*c;
        if(a==0 && b==0 && c==0)
        {
        cout<<"x=luboe 4islo  \n";
        }
        else if(a==0&&b!=0&&c!=0)
            {
            x1=-c/b;
                cout<<"x= "<<x1 << "\n";
            }
        else if(c==0)
                {
                  x1=-b/a;
                    cout<<"x1=0 \n"<<"x2= "<<x1 <<"\n";
                }
                                                  
        else 
			if (a!=0&&b==0&&c!=0)
            if(c<0&&a>0||c>0&&a<0)
            {
                x1=sqrt(-c/a);
                x2=-sqrt(-c/a);
                cout<<"x1="<<x1 << "\n";
                cout<<"x2="<<x2 << "\n";
            }
            else    
                {
                    cout<<"net resheniya,povtorite vvod \n";
                    continue;
                }   
        if(c!=0 && a!=0 && b!=0)
        {
        {
            if(d<0)
            {
                cout<<"d="<<d<<"\n";
                cout<<"d=otricatelen"<<"\n";
                cout<<"net resheniya,povtorite vvod \n";
                                         continue;
            }
            else if(d==0)
            {
                cout<<"d="<<d<<"\n";
                x1=-b/(2*a);
                cout<<"x= "<<x1<<"\n" ;
            }
     else    if(d>0)
            {
                cout<<"d="<<d<<"\n";
                x1=(-b+sqrt(d))/(2*a);
                x2=(-b-sqrt(d))/(2*a);
                cout<<"x1="<<x1<<"\n";
                cout<<"x2="<<x2<<"\n";
                }                                                
                            }
                            }
    cout<<"vixod?[y/n] \n";
    cin>>key;
    }
    while (key!='y');}
} 

void systema ()
{
	char kw;
	int t0[10],t1[10];
	double x[10],y[10];
        float a;
	int c,d,i=0,j=0;
	FILE *fp;
	do
	{
		fp=fopen("resh_system.txt","a");
		if (!fp)
		{
			printf("error\n");
		}
		else
		{
			printf("Idet zapis' v resh_systemi.txt\n");
			cout<<"\n"
			<<" Reshit sistemu:\n"			
			<<" x=at-dsin(t0)\n"
			<<" y=a-dcos(t1)\n"
			<<" Vvedite a=";
			cin>>a;
		    cout<<" Vvedite d=";
		    cin>>d;
	
		cout<<"\n"
			<<" vveddite 10 znac4eniy t0:";
		for(i=1;i<=10;i++)
		{
			cin>>t0[i];
		}
		cout<<"\n"
			<<"vveddite 10 zna4eniy  t1:";
		for(j=1;j<=10;j++)
		{
			cin>>t1[j];
		}
		for(i=1;i<=10;i++)
		{
			x[i]=(a*t0[i])-(d*cos(t0[i]));
			cout<<"x["<<i<<"]="<<x[i]<<"\n";
			fprintf(fp, "x%i=%f ",i,x[i]);	
		}
		cout<<"\n";
		fprintf(fp,"\n");
		for(j=1;j<=10;j++)
		{
			y[j]=(a-(d*cos(t1[j])));
			cout<<"y["<<j<<"]="<<y[j]<<"\n";
			fprintf(fp, "y%i=%f ",j,y[j]);
		}
		cout<<"\n";
			fprintf(fp," \n");
			fprintf(fp,"\n");
			fclose(fp);
		if (fclose(fp)!=EOF)
		{
			printf("error.file not cl");
		}
		}
		cout<<"Vixod?'[y/n]\n";
		cin>>kw;

		}
		while (kw!='y');
	}

void main ()
{
	char i,q;
	do
	{
		cout<<"\n"
			<<"               Menu              \n"
			<<"\n"
        	<<"vibirite gelaemoe deystvie\n"
			<<"1-reshinie kwadratnogo yrawneniya\n"
			<<"2-dla resheniya sistemy x=at-dsint\n"
            <<"                        y=a-dcost\n"
			<<"3-vixod iz prilogeniya\n"
			<<"\n"
		;
		cin>>i;
		switch (i)
		{
		case '1':kwad ();continue;
		case '2':systema ();continue;
		case '3':cout<<"mogete prosmotret' poslednie otveti na 2e(esli ono bilo resheno) w resh_systemi.txt\n"; break;
		default: cout<<"4itaem vnimatel'no menu\n";continue;
		}
		cout<<"Viiti iz programmi? [y/n]\n";
		cin>>q;
	}
	while(q!='y');
	}