help in transfoming C++ code into regular ansi C..

This is a discussion on help in transfoming C++ code into regular ansi C.. within the C Programming forums, part of the General Programming Boards category; the instruction for building this program is not allowing me to call functions,use iosteam ,use arrays what they want is ...

  1. #1
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    help in transfoming C++ code into regular ansi C..

    the instruction for building this program is not allowing me
    to call functions,use iosteam ,use arrays

    what they want is just If ,while,for commands , simple variable,only stdio.h
    in C

    how to transform this code into that??

    Code:
    #include <iostream>
    
    unsigned sum_of_divisors(unsigned n) {
      int result=1;
     
      for(unsigned k=2;k*k<=n;++k) {
        if(n&#37;k==0) {
          int sum_of_powers=1, power=1;
          do {
            power*=k;
            sum_of_powers+=power;
            n/=k;
          } while(n%k==0);
          result*=sum_of_powers;
        }
      }
      return n>1? (n+1)*result : result;
    }
    
    bool is_abundant(unsigned n) {
      // The body of this function can be substituted by simply                     
      // return sum_of_divisors(n)>2*n;                                             
      // This is a memoized version.                                               
       const int cache_size=1000000;
      static char cache[cache_size]={0};
      if(n<cache_size && cache[n])
        return cache[n]-1;
      bool result=(sum_of_divisors(n)>2*n);
      if(n<cache_size)
        cache[n] = 1+result;
      return result;
    }
    
    void print_if_sum_of_abundants(unsigned n) {
      for(unsigned i=1;i*2<=n;++i) {
        if(is_abundant(i)&&is_abundant(n-i)) {
          std::cout << n << " = " << i << " + " << (n-i) << '\n';
          return;
        }
      }
    }
    
    int main() {
      int limit;
      std::cout << "Enter limit: ";
      std::cin >> limit;
     
      for(unsigned i=1;i<=limit;++i)
        print_if_sum_of_abundants(i);
    }
    Last edited by transgalactic2; 12-08-2008 at 01:26 AM.

  2. #2
    CSharpener vart's Avatar
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    so where is your attemp to solve the problem?
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  3. #3
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    i changed the iosteam into stdio.h
    i wrote unsigned k; outside
    and deleted the unsigned in for

    but thats as far as my knowledge in c++ goes

  4. #4
    CSharpener vart's Avatar
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    replace std::cout << with printf
    std::cin >> with scanf
    and show the resulting code
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  5. #5
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    still its not running

    ??
    Code:
    #include <stdio.h>
    
    unsigned sum_of_divisors(unsigned n) {
      int result=1;
    unsigned k;
      for(  k=2;k*k<=n;++k) {
        if(n&#37;k==0) {
          int sum_of_powers=1, power=1;
          do {
            power*=k;
            sum_of_powers+=power;
            n/=k;
          } while(n%k==0);
          result*=sum_of_powers;
        }
      }
      return n>1? (n+1)*result : result;
    }
    
    bool is_abundant(unsigned n) {
      // The body of this function can be substituted by simply
      // return sum_of_divisors(n)>2*n;
      // This is a memoized version.
       const int cache_size=1000000;
      static char cache[cache_size]={0};
      if(n<cache_size && cache[n])
        return cache[n]-1;
      bool result=(sum_of_divisors(n)>2*n);
      if(n<cache_size)
        cache[n] = 1+result;
      return result;
    }
    
    void print_if_sum_of_abundants(unsigned n) {
      unsigned i;
      for(i=1;i*2<=n;++i) {
        if(is_abundant(i)&&is_abundant(n-i)) {
            printf("%d=%d+%d\n",n,i,n-i);
    
          return;
        }
      }
    }
    
    int main() {
      int limit;
      printf(" "Enter limit: ");
      scanf("%d",&limit);
    unsigned i;
      for(i=1;i<=limit;++i)
        print_if_sum_of_abundants(i);
    }
    Last edited by transgalactic2; 12-08-2008 at 01:55 AM.

  6. #6
    C++まいる!Cをこわせ! Elysia's Avatar
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    What does not running mean?
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  7. #7
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    i get these syntax errors from the compilers:
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|20|error: syntax error before "is_abundant"|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|20|warning: return type defaults to `int'|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c||In function `is_abundant':|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|25|error: variable-sized object may not be initialized|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|25|warning: excess elements in array initializer|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|25|warning: (near initialization for `cache')|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|25|error: storage size of 'cache' isn't constant|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|28|error: `bool' undeclared (first use in this function)|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|28|error: (Each undeclared identifier is reported only once|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|28|error: for each function it appears in.)|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|28|error: syntax error before "result"|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|30|error: `result' undeclared (first use in this function)|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|25|error: size of variable 'cache' is too large|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c||In function `main':|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|47|error: syntax error before "Enter"|
    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|47|error: missing terminating " character|
    ||=== Build finished: 11 errors, 3 warnings ===|

  8. #8
    C++まいる!Cをこわせ! Elysia's Avatar
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    Firstly, can you use / are you using C99?
    And secondly, this has little to do with C++ anymore - mostly syntax errors, undeclared identifiers and variables not defined at the start of a block.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  9. #9
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    i am using codeblocks8.02 compiler
    i dont know if its using C99

    i got a function is_abundant(unsigned n) defined as bool

    i know thats its not possible in C
    and

    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|25|error: storage size of 'cache' isn't constant|

    ??

  10. #10
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    and how to interpret this line :

    return n>1? (n+1)*result : result;

  11. #11
    C++まいる!Cをこわせ! Elysia's Avatar
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    Quote Originally Posted by transgalactic2 View Post
    i am using codeblocks8.02 compiler
    i dont know if its using C99
    Code::Blocks is not a compiler; it's an IDE.

    i got a function is_abundant(unsigned n) defined as bool

    i know thats its not possible in C
    It's possible in C99.
    Otherwise just typedef it.

    and

    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|25|error: storage size of 'cache' isn't constant|

    ??
    Make:
    Code:
    	const int cache_size=1000000;
    	static char cache[cache_size]={0};
    Into:
    Code:
    	static char cache[1000000]={0};
    C++ can take constants that can be evaluated at compile time to specify the size of an array, while C cannot.

    Quote Originally Posted by transgalactic2 View Post
    and how to interpret this line :

    return n>1? (n+1)*result : result;
    Code:
    if (n > 1)
        return (n + 1) * result;
    else
        return result;
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  12. #12
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    i did the changes you told

    i cant use bool type
    and
    i am not allowed to use typedef on the bool problem

    how to replace it with intege variables of 1 and 0??

    i get a bug that cache_size is not defined in is_abundant(unsigned n)

    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|30|error: `cache_size' undeclared (first use in this function)|

    i dont know how to define cache_size

    i cant use type unsigned only integer/long integer
    how to replace it??
    Code:
    #include <stdio.h>
    
    unsigned sum_of_divisors(unsigned n) {
      int result=1;
    unsigned k;
      for(  k=2;k*k<=n;++k) {
        if(n&#37;k==0) {
          int sum_of_powers=1, power=1;
          do {
            power*=k;
            sum_of_powers+=power;
            n/=k;
          } while(n%k==0);
          result*=sum_of_powers;
        }
      }
      if (n > 1)
        return (n + 1) * result;
    else
        return result;
    }
    
    int is_abundant(unsigned n) {
    
      // The body of this function can be substituted by simply
      // return sum_of_divisors(n)>2*n;
      // This is a memoized version.
      static char cache[1000000]={0};
    
      if(n<cache_size && cache[n])
        return cache[n]-1;
      bool result=(sum_of_divisors(n)>2*n);
      if(n<cache_size)
        cache[n] = 1+result;
      return result;
    }
    
    void print_if_sum_of_abundants(unsigned n) {
      unsigned i;
      for(i=1;i*2<=n;++i) {
        if(is_abundant(i)&&is_abundant(n-i)) {
            printf("%d=%d+%d\n",n,i,n-i);
    
          return;
        }
      }
    }
    
    int main() {
      int limit;
      printf(" "Enter limit: ");
      scanf("%d",&limit);
    unsigned i;
      for(i=1;i<=limit;++i)
        print_if_sum_of_abundants(i);
    }
    Last edited by transgalactic2; 12-08-2008 at 03:06 AM.

  13. #13
    C++まいる!Cをこわせ! Elysia's Avatar
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    Quote Originally Posted by transgalactic2 View Post
    i cant use bool type
    and
    i am not allowed to use typedef on the bool problem
    ...And why not?

    how to replace it with intege variables of 1 and 0??
    You can't. But you can use an integer or whatever that can holds values more than 0 and 1. It works, as well, but not limited to only 1 and 0.

    i get a bug that cache_size is not defined in is_abundant(unsigned n)

    C:\Documents and Settings\lun\My Documents\ass1\ass1.c|30|error: `cache_size' undeclared (first use in this function)|
    Sigh, so make a define!

    i cant use type unsigned only integer/long integer
    how to replace it??
    Unless you use C99, no.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  14. #14
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    i am restricted to these simple commands
    because we havent studied them in the course

    i cant use define


    i can use visual studio 2005
    but only a simple commands

  15. #15
    C++まいる!Cをこわせ! Elysia's Avatar
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    So hard-code them, then.
    If you haven't studied them in a course, then why are you trying to change C++ code that contains these things into C code?
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

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