String in c++

Question

Can anyone help me to correct this code and also explain it how .
The user enter a string and a character, if that character exits in the string it should show the index, otherwise it should show -1.

https://code.sololearn.com/cXa4Uspk8acy/?ref=app

Answer 1

sorry I dont know c++

Answer 2

You're code doesn't work, and it's completely normal. n can't never be equal to i since the loop breaks when i equals n. But that's not the main issue.

To input a string, that was true :
cin.getline(s, 20);
Then, you want to input a char, so, do like that:
char c;
cin >> c;

Then, the loop was wrong.
int i = 0;
for(i ; i < 20 ; i++) {
if(s[i] == c)
flag = true
... // then it was right
}

And I advise you rewriting it in a 'c++ way'.

Answer 3

After the line :
flag = true;
Add the break keyword :
if(s[i] == c) {
flag = true;
break;
}

And it doesn't show an error. It shows a warning. Simply ignore it, it doesn't matter...

Answer 4

It worked for me. When I entered Hello and then the char 'o', it outputs 4.

Maybe the problem is when you input the string then the char in SoloLearn. Do you write on a first line your string, and then on a second line the char?

I don't really see what you mean by 'assign 0 to i just in the loop'.
i is a variable that is a type of counter. So it must hold value 0, so yes, you must assign 0 to i.

Answer 5

Théophile
Thanks for your help, I edited the code but I don't know why when I assign 0 to i at the beginning (not in the loop) it shows an error.
Also , when I assign 0 to i in the loop , it always shows 20 which is the string lenght.

Answer 6

I did it but the output is not correct , also why I should assign 0 to i just in the loop?

Answer 7

Thanks Théophile
I write the character on the first line and that was my fault.
I got it ,Thanks a lot .

Answer 8

You're welcome! 👍

Answer 9

#include <iostream>
#include <string>
using namespace std;

int main() {
int i=0;
char c;
bool flag=false ;
char s[20];
cout<<"enter string: \n";
cin.getline(s,20);
cin>>c;
for (; i<20 ; i++)
{
if (s[i]==c)
{
flag = true;

break;
}
}
if (flag==true)
cout<<i;
else
cout<<"-1";

return 0;
}
Try this Its Runs

Answer 10

Curly brackets not necessary in this Case. If You Want more than one Operations for the FOR LOOP then You have to put curly brackets.

Answer 11

Rohit wadne
i know for more than one operation , we need curly brackets ; but shouldn't the IF statement iterate which each iteration of the FOR LOOP?
can you explain why the IF statement shouldn't iterate?

Answer 12

#include <iostream>
#include <string>
using namespace std;

int main() {

string c;
string s;
cout<<"enter string: \n";
getline(cin,s);
cout << "Enter char to find:";
getline(cin,c);

int flag =s.find(c);
if (s.find(c) != string::npos)
cout<<flag;
else
cout<<"-1";

return 0;
}

Answer 13

If statement Are used To check Whether some operation True Or Not. They are not Like For Loop