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pls check it for me

Discussion in 'C' started by vipul15singh, Mar 6, 2010.

  1. vipul15singh

    vipul15singh New Member

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    there is a exponential program, it has some problem in result {if x=1 and n=5 the answer must be 2.7016}
    pls tell me the problem and solution also

    Code:
    #include<stdio.h>
    #include<conio.h>
    float expo(float,float,int,float);
    float term(float,float,float);
    main()
    {
     int n;
     float e=0.0,t=1.0,x;
     static float s=1.0;
     clrscr();
     printf("\nenter variable & no ofterms:=");
     scanf("%f%d",&x,&n);
     e=expo(x,t,n,s);
     printf("\nsum=%f",e);
     getch();
     return;
    }
    float expo(float x,float t,int n,float s)
    {
     float c=1.0,e=0;
     if(t<n)
     {
      e=term(x,t,c);
      s=s+e;
      expo(x,t+1.0,n,s);
     }
      return(s);
    }
    float term(float x,float t,float c)
    {
     if(t>=1)
     {
      c=c*(x/t);
      term(x,t-1,c);
     }
      return(c);
    }
     
    Last edited by a moderator: Mar 6, 2010
  2. virxen

    virxen New Member

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    check the result again.i think it must be 2.7083

    i made 2 corrections and also i changed how scanf gets its data.

    Code:
    #include<stdio.h>
    #include<conio.h>
    float expo(float,float,int,float);
    float term(float,float,float);
    int main()
    {
     int n;
     float e=0.0,t=1.0,x;
     static float s=1.0;
     //clrscr();
     [COLOR="Red"]printf("\nenter variable:");
     scanf("%f",&x);
      printf("\nenter no of terms:");
     scanf("%d",&n);[/COLOR]
     e=expo(x,t,n,s);
     printf("\nsum=%f",e);
     getch();
     return 0;
    }
    float expo(float x,float t,int n,float s){
     float c=1.0,e=0;
     if(t<n){
      e=term(x,t,c);
      s=s+e;
      t++;
      [COLOR=Red]s=expo(x,t,n,s);[/COLOR]
     }
      return(s);
    }
    float term(float x,float t,float c)
    {
     if(t>=1){
      c=c*(x/t);
      [COLOR=Red]c=term(x,t-1,c);[/COLOR]
     }
      return(c);
    }
    
    
    
    
     
    shabbir likes this.
  3. vipul15singh

    vipul15singh New Member

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    thanks virxen, i m very happy to get sol.,pls tell me whats the actual problem in prog at (vipul.fifteen@yahoo.com)
    once again thanks
     
  4. virxen

    virxen New Member

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    a better solution is this

    Code:
    #include<stdio.h>
    #include<conio.h>
    float expo(float,float,int,float);
    float term(float,float,float);
    int main()
    {
     int n;
     float e=0.0,t=1.0,x;
     static float s=1.0;
     //clrscr();
     printf("\nenter variable:");
     scanf("%f",&x);
      printf("\nenter no of terms:");
     scanf("%d",&n);
     e=expo(x,t,n,s);
     printf("\nsum=%f",e);
     getch();
     return 0;
    }
    float expo(float x,float t,int n,float s){
     float c=1.0,e=0;
     if(t<n){
      e=term(x,t,c);
      s=s+e;
      t++;
      [COLOR=Red]return expo(x,t,n,s);[/COLOR]
     }
      return(s);
    }
    float term(float x,float t,float c)
    {
     if(t>=1){
      c=c*(x/t);
      [COLOR=Red]return term(x,t-1,c);[/COLOR]
     }
      return(c);
    }
    
    

    the error is that when you have a recursive function like above
    you must keep a sequential line between its calls and not to break it.

    for instance(each one calls its previous )

    4!=3!*4=(2!*3)*4=( (1!*1*2)*3 )*4=((0!*1*2)*3)*4

    without the return i added here you always return c as the result which is not
    changing.

    for more on this check this link
    http://www.java2s.com/Tutorial/C/0160__Function/Recursion.htm
     

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