Thread: How to display output using puchar() only ???

Hello ,

My program read in input using getchar() and then convert it into integer value. After converting into integer value , i will have to convert it into hexadecimal.

My question is : how to output the result (hexadecimal value) using only putchar() ???

I tried to output it but invalid result appear instead. ( see source code )

Code:

#include<stdio.h>

main()
{

 int i,j,ch,decimal,count;
 
 int temp;

 int hex[10], number[10];

 i=0;
 count=0;
 decimal=0;
 
 printf("Please enter your input in decimal form: ");
 ch = getchar();

 while(ch != '\n')
    {
        if('0' <= ch && ch <= '9')
         {
          decimal = decimal * 10;
          decimal = decimal + (ch - '0');
         }
      ch = getchar();
    }

 printf("Input? %d\n",decimal);

 while(decimal != 0)
    {
     hex[i] = decimal%16;
     decimal= decimal/16;
//     printf("remainder is %d\n",hex[i]);
//     printf("after divided is %d\n",decimal);
     i++;
     count++;
	}
	
   i=i-1;		
  for(j=0; j < count; j++)
     {
      number[j]=hex[i];
	  i--;
     }	

  for(j=0; j < count; j++)
  {
   putchar(number[j]);
  } 
 putchar('/n');	 
}

First of all in my view you should use gets and puts or scanf and printf instead of putchar and getchar for above mentioned problem

Originally Posted by RockyMarrone

First of all in my view you should use gets and puts or scanf and printf instead of putchar and getchar for above mentioned problem

I guess he is a beginner and wants to use putchar. Otherwise you can use printf() and itoa() and only need this

Code:

int main() 
{
 int in; char buf[10];
 printf("Please enter your input in decimal form: "); 
 scanf("%d", &in);
 printf("%s", itoa(in,buf,16));
}

edit: gets is never good, fgets is ok

Originally Posted by C_ntua

I guess he is a beginner and wants to use putchar. Otherwise you can use printf() and itoa() and only need this

Code:

int main() 
{
 int in; char buf[10];
 printf("Please enter your input in decimal form: "); 
 scanf("%d", &in);
 printf("%s", itoa(in,buf,16));
}

edit: gets is never good, fgets is ok

You told that he is a beginer and you are giving an example with scanf and printf LOL

Originally Posted by laserlight

Yes, beginners should learn how to use scanf and printf appropriately. Note that itoa() is non-standard, if we look strictly into the C standard library.

Hey Laserlight don't try to act very very smart here check out my previous post first then before writing this one here

First of all in my view you should use gets and puts or scanf and printf instead of putchar and getchar for above mentioned problem

Originally Posted by laserlight

I did, and I found your suggestion of gets() to be in need of correction, which was provided by C_ntua.

But you were talkin abt the printf and scanf i am getting what C_ntua is saying that is acceptable to me

and in that case also a newbie must know why he/she should use fgets instead of gets

I can only use getchar() and putchar() for taking into and displaying output. Because this is the requirement.

Hello ,

Here is my code. I revise it but why the putchar() can only display one character only ??

Please see the last part of the code .

Code:

#include<stdio.h>

main()
{

 int i,j,ch,decimal,count,search;
 
 int temp;

 int hex[10];
 int number[10];

 i=0;
 count=0;
 decimal=0;
 
 printf("Please enter your input in decimal form: ");
 ch = getchar();
 
 while(ch != '\n')
    {
        if('0' <= ch && ch <= '9')
         {
          decimal = decimal * 10;
          decimal = decimal + (ch - '0');
         }
      ch = getchar();
    }

 printf("Input? %d\n",decimal);

 while(decimal != 0)
    {
     hex[i] = decimal%16;
     decimal= decimal/16;
     printf("remainder is %d\n",hex[i]);
     printf("after divided is %d\n",decimal);
     i++;
     count++;
	}
	
   i=i-1;		
  for(j=0; j < count; j++)
     {
      number[j]=hex[i];
	  i--;
	  printf("number[%d] is %c\n",j, number[j]);
     }	
  printf("\n");
  for(j=0; j < count; j++)
  {
   if(number[j]==0) {putchar('0');}
   else if(number[j]==1) {putchar('1');}
   else if(number[j]==2) {putchar('2');}
   else if(number[j]==3) {putchar('3');}
   else if(number[j]==4) {putchar('4');}
   else if(number[j]==5) {putchar('5');}
   else if(number[j]==6) {putchar('6');}
   else if(number[j]==7) {putchar('7');}
   else if(number[j]==8) {putchar('8');}
   else if(number[j]==9) {putchar('9');}
   else if(number[j]==10) {putchar('A');}
   else if(number[j]==11) {putchar('B');}
   else if(number[j]==12) {putchar('C');}
   else if(number[j]==13) {putchar('D');}
   else if(number[j]==14) {putchar('E');}
   else if(number[j]==15) {putchar('F');}
   j++;
   putchar('\n');
  } 
 
}