Thread: how do I change the case of a string?

I need to create a program for my friend that accepts a string from the user (not from the command line) and displays:

-The string using upper-case letters, e.g. all lower-case letters are converted to upper-case letters

-The string using lower-case letters, e.g. all upper-case letters are converted to lower-case letter.

-The string where the first letter of each word is upper-case and all other letters in the word are lower-case.

-The string in "camel case", i.e. the first letter in the string is lower case, followed by alternating upper and lower case letters.

-And that's it :P

Here’s what I have so far, I'm completely lost now :*( if anyone could help me finish this I'd greatly appreciate it. )) also I don't want to use string commands, too easy :P I figured I'd post the entire working code so you can see what’s wrong. I've been trying to get Lower case to work, but every way I use it, it just messes up the rest of them. I want it to display the sentence you entered, then in lowercase, then in uppercase, then in first case, then in camel case. I got the sentence, upper and first case to work. The other two I can’t. Please see if you can fix it, I feel retarded lol....

Code:

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

void toUpper(char *str);
void toFirstCap(char *str);
void toCamelCase(char *str);

int main(int argc, char **argv)
{ 
char sentence[256]; 
char ch; int i = 0;
printf("Enter a string: ");
gets(sentence);
printf("\nYour Sentence:%s\n",sentence);
toUpper(sentence);
printf("\nUpper case: %s\n",sentence);
toFirstCap(sentence);
printf("\nFirstCap case: %s\n",sentence);
toFirstCap(sentence);
system("pause");}

void toUpper(char *str){
while(*str != '\0'){
if(*str >= 'a' && *str <= 'z')
{ *str -= 'd' - 'D';
} str++; }}

void chngCaseSingleCharacter(char *str, int cAse){
if(cAse == 2)
{ 
if(*str >= 'a' && *str <= 'z'){
*str -= 'd' - 'D';}
else if(cAse == 1){
if(*str >= 'A' && *str <= 'Z'){ 
*str += 'd' - 'D';
}}}}

void toFirstCap(char *str){
char b;
while( (b = *str++) != '\0'){ 
if(b == ' ' || b == '\t'){
if(*str >= 'a' && *str <= 'z')
{ *str -= 'd' - 'D'; }} 
else{
if(*str >= 'A' && *str <= 'Z') {
*str += 'd' - 'D'; }}}}

void toFirstCapSmartWay(char *str){
char b; while( (b = *str++) != '\0') 
{ if(b == ' ' || b == '\t') {
chngCaseSingleCharacter(str, 2);}
else {
chngCaseSingleCharacter(str, 1);
}}}

//void toCamelCase(char *str)
//put code 4 camel case here//

Start by INDENTING!!!

After that, loop through each string and compare each char ch for 'a' <= ch <= 'z', and if it is, subtract 'a' and add 'A' to it.

That would be the way for upstring.

Really, though. You need to learn to indent. That is really ugly up there.