Thread: Questions regarding programs

Question 1:
-----------

Code:

#include<stdio.h>
#include<conio.h>

int main(void)
{
   int a,b;
   clrscr();

     printf("Enter values for a and b\n");
     scanf("%d%d",&a,&b);
     printf("a=%d,b=%d",a,b);

   getch();
   return 0;
}

Here the question is, if i write scanf() function as scanf("%d%d ",&a,&b); or
scanf("%d %d ",&a,&b); or scanf(" %d%d ",&a,&b);, it is taking 3 inputs, rather than 2 inputs. Why like this?


Question 2:
-----------

Code:

#include<stdio.h>
#include<conio.h>

int main(void)
{
   int a=3;
   float b=3.0
   clrscr();

     if(a==b)
       printf("a and b are equal");
     else    
       printf("a and b are not equal");

   getch();
   return 0;
}

Here at execution, it is giving output as a and b are equal. Why it is like this?

Question 3:
-----------

Code:

#include<stdio.h>
#include<conio.h>

int main(void)
{
   int i;
   clrscr();

     for(i=0;i<=5;printf("%d\n",i))
	i++;

   getch();
   return 0;
}

For the above program the output is
1
2
3
4
5
6

Why?

Question 4:
-----------

Code:

#include<stdio.h>
#include<conio.h>

int main(void)
{
   int i;
   clrscr();

     for(i=1;i<=5;printf("%d\n",i++))
 
   getch();
   return 0;
}

For the above program the output is
1
2
3
4
5

But if we press every time "Enter" button then only it is printing output from 1 to 5. Why it is happening like this?

Question 5:
-----------

Code:

#include<stdio.h>
#include<conio.h>

int main(void)
{
   char another;
   int i;
   clrscr();

     do
       {
	printf("Enter a number\n");
	scanf("%d",&i);
	printf("The number is %d\n",i);
	printf("Continue(y\n)\n");
	scanf("%c",&another);
       }while(another=='y');

   getch();
   return 0;
}

Code:

#include<stdio.h>
#include<conio.h>
int main(void)
{
   char another='y';
   int i;
   clrscr();

     for(;another=='y';)
	{
	 printf("Enter a number\n");
	 scanf("%d",&i);
	 printf("The number is %d\n",i);
	 printf("Continue(y\n)\n");
	 scanf("%c",&another);
	}

   getch();
   return 0;
}

Code:

#include<stdio.h>
#include<conio.h>
int main(void)
{
   char another='y';
   int i;
   clrscr();

     while(another=='y')
	{
	 printf("Enter a number\n");
	 scanf("%d",&i);
	 printf("The number is %d\n",i);
	 printf("Continue(y\n)\n");
	 scanf("%c",&another);
	}

   getch();
   return 0;
}

For the above 3 programs the syntax is correct, but if we execute the each and every program, the loop is repeating only 2 times. After 2 times the program is terminating. Why and what is the corrcet programs for the above 3 progarms?

Question 6:
-----------

Code:

#include<stdio.h>
#include<conio.h>
int main(void)
{
   clrscr();

     for(;;);
	printf("%d\n",i);

   getch();
   return 0;
}

What this program mean?



The statement "for loop works faster than a while loop" is correct?

for q.no.2
the int is getting promoted to a float.
for q.no.3
for loop works as
1.initialize
2.test
3.execute body of the loop
4.go to incrementation part
for q.no.4
u've not put a semicolon after the for loop that's why getch() is acting as the body of the loop and every time enter is to be hit.to rectify it simply put a semicolon after the for loop
for q.no.6
it is an indefinite for loop if u define variable 'i'.otherwise it will throw an error.