Find character occurrences in a file c++

[salokin]

Could you please tell me, how to count the occurrence of each individual letter
(for example "d","c",....) in a given file that contain random letter sequence (for example" asjdjuendncnwjashdnd...") and display the answer as percentage (for example d found 10 times so it would be 15% of the file letters).
Thanks in advance.

[codekiddy]

you would use Standard template library classes to achive that task:
ifstream class to read a file for example.

this web site has nice tutorial on how to use STL classes.. just click on the link "Reference" here on the left upper corner.

[salokin]

My problem is that i don't know how to count the characters in the file. i manage to open the file and read from it but i don't know how to process the information in the file and find how many d for example are in the file.

[codekiddy]

http://www.cplusplus.com/reference/iostream/ifstream/

check functions peek and get to extract and get the char.

[Tralon]

/*
1.sorry,I am not good at english. 希望下面的code对你有用。
2.统计infile.txt文件中每个letter及其出现的次数
3.example：
文件内容：
dog cat cat dog pig
pig dog deck monkey
goose goose pig
t t ttt ttt
输出：
a 2
c 3
d 4
e 4
g 8
i 3
k 2
m 1
n 1
o 8
p 3
s 2
t 10
y 1

sum = 52; //letter总数
*/

#include <string>
#include <map>
#include <fstream>
using namespace std;
int main()
{
map<char, int>myMap; //定义map容器
ifstream infile("infile.txt"); //打开文件流

char letter;
while( infile >> letter) // 将文件中内容读入letter
{
myMap[letter]++; //将文件中出现的letter以 <key value>的形式存储到myMap中
}

map<char,int>::const_iterator iter;
int sum = 0;
for( iter = myMap.begin(); iter != myMap.end(); ++iter)
{
cout << iter->first <<" " << iter->second << endl; //putout the “letter” 和它出现的次数
sum += iter->second; //计算letter总数
}

cout << sum << endl;

}