Hatam nerde? ---C'de

#include<stdio.h>
 #include<ctype.h>
 #define NSIZE 10
 
 int touppercase(char b[]) {
 	
 	for(int i=0;b[i] !='\0';i++){ 
 		b[i]=toupper(b[i]); 
 		i++;
 	}
 	return b[];
 	 
 }
 int main() {
 
 	char word[NSIZE];
 
 	printf("please,enter a string(max 10 characters)");
 	scanf("%s", word);
 	printf("%s", touppercase(word[]));
 
 	getchar();
 	return 0;
 }

#include<stdio.h> 
 #include<ctype.h> 
 #define NSIZE 10 
  
 int i; 
  
 char touppercase(char b[]) { 
  
 	 
 	for (i = 0; b[i] != '\0'; i++) { 
 		b[i] = toupper(b[i]); 
 	} 
 	return b[i]; 
 } 
  
 int main() { 
 	 
 	char word[NSIZE]; 
 	int a, b; 
  
 	printf("please,enter a string(max 10 characters)\n"); 
 	scanf("%s", word); 
 	printf("Your Word=%s\n", word); 
 	printf("%s\nYour word's has %d characters\n", touppercase(word),i);

 
 char * touppercase(char b[]) { 
  
  
 	for (i = 0; b[i] != '\0'; i++) { 
 		b[i] = toupper(b[i]); 
 	} 
 	return b; 
 }