Inserting into a string c++

Question

If i want to insert the same character in a string a number of times that the user enters For example:

int n=30; string s=""; for(int i=0; i<n; i++) { s=s+"M"; }

is there a more efficient way to make the same process in less time? because if n is a big number it will take the program quite long time to run

Neozaru · Accepted Answer · 2013-02-10 10:25:23Z

4

According : http://www.cplusplus.com/reference/string/string/append/ Case n°5 : Filling a string

str.append (14, 'd');

Will append 14 times the character 'd' in your string

answered Feb 10, 2013 at 10:25

Neozaru

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2 Comments

t1w Over a year ago

i was just about to write the same thing. kudos :)

Rapptz Over a year ago

This is still linear in count though.

user529758 · Accepted Answer · 2013-02-10 10:25:30Z

Not sure if it's faster, but it's surely of a better style:

s += std::string('M', n);

Rapptz · Accepted Answer · 2013-02-10 10:32:33Z

The answer is a more likely no, there isn't a more efficient way of doing it. Most operations will actually be linear in count. Including constructing an alternative string, appending to it using std::string::append and even std::fill. A good way to maybe get a speed up though is by using s.push_back('M') and by possibly making a reserve call but even then it won't be noticeably faster, if at all.

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