Thread: help on loop

any one know who to make loop on this??

how to loop over and over again till i prest "-1" then only the program end

Code:

#include<stdio.h>
#include<string.h>

void main()
{
char strsrc[5];
char strtmp[5];

printf("\n Enter a five-digit number ( -1 to end ): "); gets(strsrc);

strcpy(strtmp,strsrc);
strrev(strtmp);

if(strcmp(strsrc,strtmp)==0)
printf("\n %s is a palindrome\n",strsrc);
else
printf("\n %s is not a palindrome\n",strsrc);
}

FAQ Entry: How do I get a number from the user (C)
FAQ Entry: Get a line of text from the user/keyboard (C)
Tutorial: Loops in C

where do i need to put the while?

Mats you mean <math.h>

?

Code:

#include<stdio.h>
#include<string.h>

void main()
{
char strsrc[5];
char strtmp[5];

printf("\n Enter a five-digit number ( -1 to end ): "); gets(strsrc);

strcpy(strtmp,strsrc);
strrev(strtmp);
while (strsrc!=-1)
if(strcmp(strsrc,strtmp)==0)
printf("\n &#37;s is a palindrome\n",strsrc);
else
printf("\n %s is not a palindrome\n",strsrc);
}

this not working cuz its says !=' : no conversion from 'const int' to 'char *'

That's because you don't compare strings with !=. You compare strings with strcmp.

Also, you would need to compare with the string "-1", not the number -1.

then its must be like this?

Code:

#include<stdio.h>
#include<string.h>

void main()
{
char strsrc[5];
char strtmp[5];

printf("\n Enter a five-digit number ( -1 to end ): "); gets(strsrc);

strcpy(strtmp,strsrc);
strrev(strtmp);
while (strcmp!="-1")
if(strcmp(strsrc,strtmp)==0)
printf("\n &#37;s is a palindrome\n",strsrc);
else
printf("\n %s is not a palindrome\n",strsrc);
}

this still erroe thou...

So if "you" did this one right:

Code:

if(strcmp(strsrc,strtmp)==0)

why do you think it should be

Code:

while (strcmp!="-1")

?

because matsp says use while, and i dono where to used the while...

Who's complaining about the while? It's the only thing right about that second quoted line.

i still dont get you sir.. do you mind correct that code please..

Code:

while (strcmp(strcmp, "-1") !=0) {
...
}

You cannot use operators like !=, == with strings. Besides, strcmp is not even a string, it is a pointer to an array of char.

Why test with -1 for a string by the way?? I don't know if this will work. If you enter -1 that will be two characters saved inside strsrc. If you reverse them, with strrev(), I assume you will have 1- as a string, not -1. You can just press "quit" or 'q' to quit the program...

its not working,

any way you got any idea on how to do this in other way? where if i keyin -1 it will terminate the program..

something like this

Code:

Enter a five-digit number ( -1 to end ): 21212
21212is a palindrome

Enter a five-digit number ( -1 to end ): 16633
16633 is not a palindrome

Enter a five-digit number ( -1 to end ): -1