String to int

Question

I wrote this code to convert number string to int and compare:-
#include<stdio.h>
int str(char S1[],char S2[])
{
int x=0,y=0,i;
for(i=0;S1[i]!='\0';i++)
{
x*=10;
int m=S1[i];
x+=m;
}
for(i=0;S2[i]!='\0';i++)
{
y*=10;
int m=S2[i];
y+=m;
}
if(x>y)
return 1;
if(y<x)
return -1;
if(x==y)
return 0;
}
int main()
{
char S1[100],S2[100];
gets(S1);
gets(S2);
int a = str(S1,S2);
if(a==1)
printf("S1 is greater than S2");
else if(a==-1)
printf("S2 is greater than S1");
else
printf("Both are equal");
return 0;
}
but x and y are storing garbage values. why is it so? please help.

Answer 1

If you compare two codes together, you most likely find the answer. In fact, when you are trying to invent the wheel again, weird things might happen!

Answer 2

Here is a workable version of your problem. Notice that GCC compiler no longer supports gets function.
[http://cpp.sh/2bbwp]
// You can't run it on SL
[https://code.sololearn.com/cLnhWQ6YL7x6]

Answer 3

I appreciate that, sir. From now on I'll try my best to reduce those kind of mistakes.

Answer 4

Another way might be using stringstream facilities to do such thing. Here is an ad-hoc solution for an average calculator program .
https://code.sololearn.com/cn62B9g73skE/?ref=app

Answer 5

Of course sir. It's probably the worse solution in terms of considering the limits, but at least gives some clue to our friend of how he can reach to a convincing output.

Answer 6

As a clear example, see this fragment.
if(x>y)
return 1;
if(y<x) // is the same sa (x > y)
return -1;
if(x==y)
return 0;

Answer 7

Bookmarked. Thanks again. :)

Answer 8

Well
There is a function called
atoi and itoa which converts string to integer and integer to string respectively
Try that out!
Not sure but I think it's in the stdlib header file

Answer 9

so can you pls tell me what wrong with my code?

Answer 10

I did that minus of '0' still same thing

Answer 11

I don't understand and how is garbage stored in a as well. a takes value from the function and the function returns only 3 values

Answer 12

I don't have to use and library func

Answer 13

why isn't mine working but?

Answer 14

I have done everything same. just I used gets.

Answer 15

so what's difference

Answer 16

but I have done the same thing. just x>y instead of y<x. so why isn't mine working?