replacing a substring of a string with another string

How can I use string.replace() to do something like:

Code:

---

string str, str2, str3;
str  = "an adequate amount of text";
str2 = "amount of ";
st3 = "";

str.replace(str2, str3); // an adequate text

//or
str  = "an adequate amount of text";
str3 = "[how did this get here?]";

str.replace(str2, str3); // an adequate [how did this get here?] text

---

From looking at the documentation, it seems that replace() will not replace more than the amount of text it's replacing.

replace() has many forms. http://www.cplusplus.com/reference/s...g/replace.html

I suspect the first one will suit your needs.

Code:

---

string& replace ( size_t pos1, size_t n1,  const string& str );

---

For example, this should print 1cat4.

Code:

---

string original = "1234";
string replace = "cat";
// replace original[1] .. original[2] ("23") with "cat"
original.replace(1, 2, replace);
cout << original;

---

Hopefully I thought that through correctly . . . and hopefully I've answered your question.

[edit] In your first case, maybe you want something like this.

Code:

---

string str, str2, str3;
str  = "an adequate amount of text";
str2 = "amount of ";
st3 = "";

while(1) {
    // search for an occurance of str2 in str
    size_t found = str.find(str2);

    // if such a substr was found,
    if(found != string::npos) {
        // replace it with str3
        str.replace(found, str2.length(), str3);
    }
    else break;  // if the substring wasn't found, exit the loop
}

---

See also http://www.cplusplus.com/reference/s...ring/find.html
[/edit]

You have to find str2 in str before calling replace. The find function will return an index which can be passed to replace (along with the length of str2) to indicate the location of the substring to be removed.

Ah, thank you. I read the example wrong, and it looked like replace(p, n, str) only replaced a maximum on n bytes.