CODEWITHSUNDEEP
c++substr
Bal Pota
Bal Pota

Reputation: 65

I don't get what I want with substr

I want to get all the sub string possible, there is the following code for it (with all library included), which n is the length of the string s :

long substrCount(int n, string s) {
    string sub;
    vector<string> s2;
    for(int i = 0; i<n; ++i){
        for(int j = 0; j <= n-i; j++){
            sub = s.substr(i,j);
            if(sub != "")
                s2.push_back(sub);
        }
}

But when I tried with the main for the string "asasd", I get

> s2
> ={a,as,asa,asas,asasd,a,as,asa,asas,asasd,s,sa,sas,sasd,a,as,asa,asas,asasd,s,sa,sas,sasd,a,as,asd,a,as,asa,asas,asasd,s,sa,sas,sasd,a,as,asd,s,sd,a,as,asa,asas,asasd,s,sa,sas,sasd,a,as,asd,s,sd,d}

I do not understand why, the index i is from 0 to n. I should have the string beginning by 's' just after the first asasd.

Upvotes: 2

Views: 67

Answers (2)

AngryParticle
AngryParticle

Reputation: 1539

Since you did not provide enough detail in your question. I can provide you with an alternative. For this example I don't use a vector

For example:

#include <iostream>
#include <string>


void subString(std::string, int);


int main()
{
    std::string s2 = "asad";
    subString(s2, s2.length());
    return 0;
}

void subString(std::string s, int n)
{

    for (int i = 0; i < n; i++)
    {
        for (int j = 1; j <= n - i; j++)
            std::cout << s.substr(i, j) << std::endl;
    }
        
           
}

Output:

a
as
asa
asad
s
sa
sad
a
ad
d

Upvotes: 1

matteo nunziati
matteo nunziati

Reputation: 360

Because first you fix i to 0 and you iterate over the entire j-based loop, then you increment i to 1and re-do the j based loop, and so on... You can check this easily with a debugger.

Upvotes: 0

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