Question

How to convert part of a string between two indexes to lowercase in C++

Answer 1

#include <iostream>
   
using namespace std;
    
string convert_part_to_lowercase(string s, int idx_from, int idx_to) { 
    if (idx_from < 0 || idx_to > s.length()) return s;
             
    for (int i = 0; i < s.length(); i++) {
         if ((i >= idx_from && i <= idx_to) && (s[i] >= 65 && s[i] <= 90)) {
             s[i] = tolower(s[i]);
         }
    }
    return s;
}
    
int main() {
    string s = "CPP PROGRAMMING"; 
        
    s = convert_part_to_lowercase(s, 2, 4);
    cout << s << endl;
     
    s = convert_part_to_lowercase(s, 9, 11);
    cout << s;
}
   
   
    
/*
run:
    
CPp pROGRAMMING
CPp pROGRammING
    
*/

 

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