C++ program to capitalize first and last letter of each word in a line

C++ program to capitalize first and last letter of each word in a line

#include <bits/stdc++.h>
using namespace std;

void capitalize(char* arr,int i){
//ascii value of each lower case letter-ascii value
//of each uppercase letter=32
//i is the length of line
unordered_set<int> table;
table.insert(0); //index of first letter of line
table.insert(i-1);//index of last letter of line

for(int j=1;j<i;j++){
if(arr[j]==' '){
// last letter of word is before
//space & first letter of word is after space
//check index already present in hash table or not
if(table.find(j-1)==table.end())
table.insert(j-1); //if not insert index
//check index already present in hash table or not
if(table.find(j+1)==table.end())
table.insert(j+1); //if not insert index
}
}
//capitalize
for(auto it=table.begin();it!=table.end();it++)
arr[*it]-=32;
printf("converted input line is: ");
//printing
for(int j=0;j<i;j++)
printf("%c",arr[j]);
printf("\n");
}

int main(){
//store the input line
char arr[100];
char c;
int i=0;

printf("input the line.....\n");
scanf("%c",&c);
while(c!='\n'){
arr[i++]=c;
scanf("%c",&c);
}
capitalize(arr,i);

return 0;
}

Output

First run:
input the line.....
hello world
converted input line is: HellO WorlD

Second run:
input the line.....   codevidyalay is a great platform for geeks
converted input line is:  CodevidyalaY IS A GreaT PlatforM FoR GeekS