Replace last word in string with another string

Question

string str="My name is abc"
string name="logan"

I want to replace 'abc' with string name in console application c#.

Answer 1

You could use the String.Format-Function.

There you can replace fragments inside a String with a value you choose:

string str = "My name is {0}"; // the {n} defines the parameter-index, you can add as many parameters you want: {0}, {1}, {2}, ...
string name = "Logan"; // your input

string replace = String.Format(str, name) // multiple parameters possible

Console.WriteLine(replace);
// My Name is Logan

Answer 2

Assuming you can't make changes in your string:

string str = "My name is abc";
string name = "logan";
    
int lastIndex = str.LastIndexOf(" ");
if (lastIndex > 0) {
    str = str.Substring(0, lastIndex + 1) + name;
}

Console.WriteLine (str);