The minimum positive period in periodic string

Enumeration answer

for(int i=1;i<=len;i++) {
        if(len%i==0) {
            k=1;
            for(int j=i;j<len;j++) {
                if(s[j]!=s[j%i]) {
                    k=0;
                    break;
                }
            }
            if(k) {
                cout<<i<<endl;
                break;
            }
        } 
    }