Convert small letter to capital letter - c

Question

I'm trying to convert string in small letter to capital letter.
I got some error (access volation)
what whould do?
int main()
{
char str[10];
int i=0;
scanf("%s", &str);
while (str[i] !=0)
{
str[i] += -32;
printf("%s", str[i]);
}
return 0;
}
thx

Answer 1

If you enter a string longer than 9 characters, scanf() will try to write past the end of your string buffer.
Your while-loop never terminates as you never change i.
You should use "%c" as format string in your printf() call, since you are wrting characters, not null-terminated strings.

Answer 2

int main()
{
char str[10];
int i=0;
scanf("%s", str);
while (str[i] != 0)
{
str[i] += -32;
i++;
}
printf("%s", str);
return 0;
}
and of course, you must check overflow of str...

Answer 3

As cprogrammer said
You better use toupper
/* toupper example */
#include <stdio.h>
#include <ctype.h>
int main ()
{
int i=0;
char str[]="Test String.\n";
char c;
while (str[i])
{
c=str[i];
putchar (toupper(c));
i++;
}
return 0;
}
But if not, and you want to do it your way
int main()
{
char str[10];
int i=0;
scanf("%s", &str);
while (str[i]!='\0' && i<10)
{// You forgot this: '\0' instead of 0 and also i<10
str[i] += -32;
printf("%c", str[i]);//char, not string
i++; //And this
}
return 0;
}

Answer 4

There are few mistakes here:
scanf("%s", &str); - since str is a pointer to char, you don't need to give its address, but scanf("%s", str);. (and as sven said, it's unsafe)
while (str[i] !=0) this is an endless loop, you should increment i at the end of the while block.
str[i] += -32; will modify any char you're at, you should check if this is a lower case any time, for example:
if (str[i] >= 'a' && str[i] <= 'z'){
str[i] -=32;
} //couldn't format this line for some reason....
printf("%s", str[i]) is again wrong way to use printf, since %s expects to char*, and str[i] is a char. instead, use printf("%c", str[i]) which expects a char

Answer 5

You better use toupper
/* toupper example */
#include <stdio.h>
#include <ctype.h>
int main ()
{
int i=0;
char str[]="Test String.\n";
char c;
while (str[i])
{
c=str[i];
putchar (toupper(c));
i++;
}
return 0;
}

Answer 6

#include<stdio.h>
#include<conio.h>
#include<string.h>
void main();
{
int i, count;
char str[200];
clrscr();
printf("Enter a string");
scanf("%s", str);
count = strlen(str);
for(i=0; i<=count; i++)
{
if((str[i] >= 97) && (str[i] <= 122))
{
str[i] = str[i] - 32;
}
}
printf("%s", str);
getch();
}

Answer 7

You can use Bitwise AND ( & ) operator technique to make small letter to capital letter.
char ch = letter & 223; [letter = a-z] // Now ch is all time capital letter