toupper command

[dmkanz07]

Hello everyone,

I am working on a problem and I am not sure of the syntax for the toupper command. What I am trying to solve is when a user enters a string of characters C goes out and changes them to all upper case.

Here is what I have so far using a char array and gets and puts commands just not sure in the puts command how you integrate the toupper.

Thanks in advance

DMKanz07

#include <stdio.h>
#include <ctype.h>

/* Function main begins program execution */ 
int main()
{
    /* Create char array */
    char s [ 100 ];
    
    printf( "Enter a line of text: " );
    
    /* Use gets to read line of text */
    gets( s );
    
    printf( "\n" );
    
    printf( "The line printed in UPPER case: " );
    puts ( toupper ( s ) );
    
    printf( "\n" );
    
    /* Indicates successful termination */
    return 0;
    
} /* End Main */

[Happy_Reaper]

Why not to use gets.

As for the toupper stuff, the function takes in a char and returns its upper-case equivalent.

So if you'd want to convert a string to all upper case, you'd have to loop through all its chars and send them through toupper.

[dmkanz07]

Does toupper only convert one character at a time?

Thanks

DMKanz07

[Happy_Reaper]

Yes :

toupper.

[divineleft]

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

/* Function main begins program execution */
int main()
{
        /* Create char array */
        char s [ 100 ];
        int i;
        printf( "Enter a line of text: " );

        /* Use gets to read line of text */
        gets( s );
        printf( "\n" );

        /* Loop through the array and change every character
         * to its uppercase equivilant */
        for(i = 0; i < strlen(s); ++i)
        {
            s[i] = toupper(s[i]);
        }

        printf( "The line printed in UPPER case: " );
        puts (s);

        printf( "\n" );

        /* Indicates successful termination */
        return 0;

} /* End Main */

although i would recommend using fgets instead of gets.

[dmkanz07]

What is the difference between gets and fgets? I found examples of fgetc but not fgets ( Deitel C how to program ).

DMKanz07

[laserlight]

fgets() allows you to specify string length, gets() does not. As such, there is the risk that the buffer will be overrun when using gets().

[dwks]

This is a bad idea:

for(i = 0; i < strlen(s); ++i)

strlen() is rather expensive to execute, so you should save the result.