Problem with Strings and Conversions

Hi, I have a problem understanding how to convert a string of letters inputted from the user into the function toupper.
ex. input: asdf

output: ASDF

Code:

#include <stdio.h>
#include <ctype.h>
#define SIZE 50

//void ToUpperCase(char, char);

int main (void)
{
int i;
char s1[SIZE];
char s2[SIZE];

printf("Please Enter the First String: ");
scanf("%s", &s1);

printf("\nPlease Enter the Second String: ");
scanf("%s", &s2);

printf("\n");

for (i=0; i<=SIZE; i++)          /*Heres where problem is*/
printf("%s,
isalpha(s1[SIZE]) ? "Is " : "Is not ", "a letter");

//ToUpperCase(s1, s2);

return 0;
}

//void ToUpperCase(char, char){

I don't understand how to get a scanned input into a function such as toupper or isalpha?
Any help is greatly appreciated.!

You need to run through each character in the string converting its case. You can loop through characters until you reach the \0 at which point you want to break it.

How abouts would I do that?
like this...
for (i=0; i<=SIZE; i++)
if (s1[i]?>>>>>?

is this the approach, i understand how i would do this up till this point ?>>>>?

for (i=0; i<=SIZE; i++)
you should stop when the nul- char is encountered
also SIZE index is out of bounds
so

Code:

for (i=0; s1[i] != '\0' && i < SIZE; i++)

printf("&#37;s,
isalpha(s1[SIZE]) ? "Is " : "Is not ", "a letter");

you want access the i-th element

Code:

printf("%c is %sa letter", s1[i] , isalpha(s1[i]) ? "" : "not ");

with toupper
it will be something like
s2[i] = toupper(s1[i]);

and do not forget to copy the nul-char also

I placed this into my code but it comes out different, it only checks the first letter. I need it to check every letter inputted by the user.

Show your latest code

Drop the &'s when you read strings with scanf().

Note that you're missing a double quote in your code. Since it evidently compiled, it leads me to think that you're just copying your code by hand. (Or maybe you just fixed it.) If the former is true, you should post your real code. There's always the chance that a problem in your code that gets lost when you transcribe it.

Code:

#include <stdio.h>
#include <ctype.h>
#define SIZE 50

void ToUpperCase(char, char);

int main (void)
{
int i=0;
char s1[SIZE];
char s2[SIZE];
 
printf("Please Enter the First String: ");
scanf("&#37;s", &s1[i]);


printf("\nPlease Enter the Second String: ");
scanf("%s", &s2); 

printf("\n");



for (i=0; s1[i] != ('\0' && i < SIZE); i++)
printf("%c is %s letter", s1[i] , isalpha(s1[i]) ? "a" : "not a ");


 
//ToUpperCase(s1, s2);

return 0;
}

//void ToUpperCase(char, char){

//int i;

//for (i=0; i<=SIZE; i++)
//printf("%s", s1
//isalpha(s1[i]) ? "Is " : "Is not ", "a letter");

I am so confused with this?

Code:

s1[i] != ('\0' && i < SIZE)

That's not what you want. You're saying, "while the character I'm looking at is not equal to the truth of (zero and ...)". 0 && anything is always zero. So you're saying, basically,

Code:

s1[i] != 0

Yes, that happened to work, but by fluke! Either use the above code directly or something like

Code:

s1[i] != '\0' && i < SIZE

Note that you can ommit parameter names in prototypes, but not in function definitions. (Those are the ones with curly braces.)

Code:

scanf("%s", &s1[i]);

That happens to work, too, because i is zero. But really, all you need is this.

Code:

scanf("%s", s1);