CODEWITHSUNDEEP
carraysstringchar
Claudio Cortese
Claudio Cortese

Reputation: 1380

Transforming the first char of every word in a sentence to uppercase

I'm currently studying C, if this question seems an easy one or a newbie ones, then you know why. Also I already searched here on SO before posting this question. It seems that there are a lot of them but they are not about C, instead Java, php and others.

I'm working on a simple program that has to transform the first char of every word uppercase. For example if the input is :

hello my name is claudio

the output would be

Hello My Name Is Claudio

This is what I coded so far : 

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

int main(void){

        char sentence[21] = {'\0'}, sentence2[21] = {'\0'}, *token = NULL;

        fgets(sentence,21,stdin);

        token = strtok(sentence," ");

        while(token != NULL)
        {
                *token = toupper(token[0]);
                strcat(sentence2,token);
                token = strtok(NULL," ");
        }

        puts(sentence2);

return 0;

}

The output is :

MyNameIsClaudio

Obviously that's not what I was expecting, as explained above. I thought that I would have been able to solve the problem simply adding a space like that:

token[strlen(token)+1] = ' ';
strcat(sentence2,token);

But again, the output is not the one expected :

MyAmeSLaudio

Hence, to achieve the desired result I tried :

null_char = strrchr(token,'\0');
*null_char = ' ';

But neither this seems to be the right way. Currently I'm am on a dead end. Can somebody give me a hint on how I can accomplish what I'm trying to do?

Upvotes: 3

Views: 95

Answers (3)

chux
chux

Reputation: 154335

Alternative: walk the array

strtok() looses the space delimiters. This approach maintains groups of spaces.

Walk through the sentence[] array and for each letter after a space, insure it is uppercase.

fgets(sentence1, sizeof sentence1, stdin);

int precious_space = 1;
size_t len = strlen(sentence1);
for (size_t i = 0; i <= len; i++) {
  sentence2[i] = previous_space ? toupper((unsigned char) sentence1[i]) : sentence1[i];
  precious_space = sentence1[i] == ' ';
}  
fputs(sentence2, stdout);

Alternative loop. See @l3x

size_t i
for (i = 0; sentence1[i]; i++) {
  sentence2[i] = previous_space ? toupper((unsigned char) sentence1[i]) : sentence1[i];
  precious_space = sentence1[i] == ' ';
}  
sentence2[i] = '\0';

Upvotes: 3

dbush
dbush

Reputation: 224387

You just need to concatenate a space after concatenating the converted string:

strcat(sentence2,token);
strcat(sentence2," ");

Upvotes: 3

cleblanc
cleblanc

Reputation: 3688

You could just add this line to put the spaces back in

    while(token != NULL)
    {
            *token = toupper(token[0]);
            strcat(sentence2,token);
            token = strtok(NULL," ");
            if (token)
              strcat(sentence2, " ");
    }

Upvotes: 0

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