# Find indices of all occurrence of one string in other in C++

C++Server Side ProgrammingProgramming

Suppose we have string str, and another substring sub_str, we have to find the indices for all occurrences of the sub_str in str. Suppose the str is “aabbababaabbbabbaaabba”, and sub_str is “abb”, then the indices will be 1 9 13 18.

To solve this problem, we can use the substr() function in C++ STL. This function takes the initial position from where it will start checking, and the length of the substring, if that is the same as the sub_str, then returns the position.

## Example

Live Demo

#include<iostream>
using namespace std;
void substrPosition(string str, string sub_str) {
bool flag = false;
for (int i = 0; i < str.length(); i++) {
if (str.substr(i, sub_str.length()) == sub_str) {
cout << i << " ";
flag = true;
}
}
if (flag == false)
cout << "NONE";
}
int main() {
string str = "aabbababaabbbabbaaabba";
string sub_str = "abb";
cout << "Substrings are present at: ";
substrPosition(str, sub_str);
}

## Output

Substrings are present at: 1 9 13 18
Published on 19-Dec-2019 08:16:09