Question

Convert the C program into a C++ program.Replace all C input/output statements with C++ statements (cin, cout, cin.getline) .

Re-make the func function by the following prototype:

• void func( double, double &);

#include
int user_interface();
double func(double);
void print_table();

int main (int argc, char *argv[]) {

   print_table(user_interface());

   return 0 ;

}

int user_interface(int val){
   int input = 0;
   printf("This function takes in x and returns an output\n");
   printf("Enter Maximum Number of X:");
   scanf("%d", &input);
   while(input <= 0) {
       printf("integers only\n");
       while(getchar() != '\n');
       scanf("%d", &input);
   }
   return input;
}
double func(double x){
   int result;
   if(x<5){
       result = x*x;
   }
   else if ( x < 10 ) {
       result=x*x - 3*x -10;
   }
   else {
       result = x*x -7*x -8 ;
   }
   return result;
}

void print_table(int val){
   double x;

   printf("%7c%14c\n",'x','y');
   for (x = 0 ; x < val ; x +=.5 ) {
       printf("%10.2f%14.2f\n", x , func(x));
   }

}

Answer 1

The C++ equivalent for your code is as:

************************myProg.cpp***************************

#include <iostream>
#include <iomanip>

using namespace std;

int user_interface();
void func(double,double&);
void print_table(int);

int main (int argc, char *argv[]) {

print_table(user_interface());

return 0 ;

}

int user_interface(){
int input = 0;
cout<<"This function takes in x and returns an output"<<endl;
cout<<"Enter Maximum Number of X:"<<endl;
cin>>input;
while(input <= 0) {
cout<<"integers only"<<endl;
//clear the buffer
cin.sync();
cin>>input;
}
return input;
}
void func(double x,double &result){

if(x<5){
result = x*x;
}
else if ( x < 10 ) {
result=x*x - 3*x -10;
}
else {
result = x*x -7*x -8 ;
}

}

void print_table(int val){
double x;
double result;
cout<<"\tx\t\t\ty"<<endl;
for (x = 0 ; x < val ; x +=.5 ) {
   func(x,result);

   cout<<"\t"<<fixed<<setprecision(2)<<x<<"\t\t\t"<<result<<endl;

}

}