can anyone help me to invert c++ code to c code....

[benjaminwan]

#include<stdio.h>
int is_prime(int x);
int main(){
    char again;
    int x = 17;
    int count = 0;
    again = 'y';
 
    cout << "The prime numbers less than or equal to "<< x <<" are:" << endl;
                    for(int i=2 ; i<=x ; i++){
                            if(is_prime(i)){
                            cout << "\t\t" <<i << endl;
                            count ++;}
                            }
                    cout << "The total count of prime numbers is: "<< count<<endl << endl << endl;      
 
    while (again == 'y' || again == 'Y')
    {     
          cout << "Enter a 3-digit positive integer: ";
          cin >> x;
          int count = 0 ;
          for(int i=2; i<=x ; i++){
                            if(is_prime(i)){
                            cout << "\t\t" <<i << endl;
                            count++;}
                            }
                    cout << "The total count of prime numbers is: "<< count <<endl << endl << endl;      
          cout << "Would you like enter the number again? (y/n) " ;
          cin >> again;
          cout << endl;
 
          if(again == 'n' || again =='N')
           cout << "<<<<< Program Completed >>>>>" << endl;
          }  
 return 0;   
}
 
 
int is_prime(int x){
     if (x==2)
        return 1;
     for (int i = 2; i < x ; i++){
         if(x%i==0)
             return 0;}
     return 1;
     }

[Markus]

Glancing through your code, the only things that I see that will need changing are the cin and cout statements.

For the C alternatives, see printf() (cout) and scanf() (cin).

Mark.

P.S. Please see the posting guidelines on how to ask a question, specifically the part on using [code] tags.

[spiralfire]

@Markus
Yep, in c there is no cin and cout, so use printf and scanf.

But theres something else:
* On pure C variables declarations are the first lines of each function.
* this statement:

for(int i=2 ; i<=x ; i++){ 

isn't allowed in C, you can't declare a variable in the for statement, in the beginning of the function as stated before.

[JonathanS]

C99 allows that type of declaration:
http://bytes.com/topic/c/answers/698...claration-loop
it depends on with what standard of C you are looking to comply.

[Banfa]

That's true JonathonS but most C compilers, even if the are C99 compliant*, still default to C89 and so wont support this unless they have been specifically configured to.


* Or at least as compliant as possible since there are no fully C99 compliant compilers yet.