C++ .find()

The .find() method returns the index of the first occurrence of the specified string or character. If no result is found, string::npos is returned instead.

Note: string::npos will often be shown as the highest possible value of type size_t.

Syntax

stringName.find(sequence, position, count)

The following arguments are applied to the .find() method:

• sequence: the char or string to be searched for.
• position (optional): the index to start the search at (defaults to 0).
• count (optional): the number of characters that must match (defaults to the length of sequence).

Examples

The following example searches for izz in the food string:

#include <iostream>
#include <string>

int main() {
  std::string food = "pizzabagel";
  std::cout << food.find("izz");
  // Output: 1
}

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A starting index can also be specified:

#include <iostream>
#include <string>

int main() {
  std::string food = "pizzabagel";
  std::cout << food.find("izz", 2);
}

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The output for the snippet above would look like this:

18446744073709551615

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The output 18446744073709551615 represents the string::npos constant that indicates a match was not found with the given parameters. The sequence, izz, begins at index 1 while the call to the .find() method begins at index 2. Therefore, it is outside of the search range and a matching index was not found.

Searching for a sequence not in the string also returns string::npos. The following example searches for bad which is not in string food:

#include <iostream>
#include <string>

int main() {
  std::string food = "pizzabagel";
  std::cout << food.find("bad");
}

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The output for the snippet above would look like this:

18446744073709551615

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Codebyte Example

However, if the previous example is changed to search for the first two characters of bad instead, then a result is found:

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