c++ 如何把一个变量加入到字符串中 c++中怎样才能将一串字符存入一个字符串变量？

c++\u4e2d\u600e\u4e48\u628a\u4e00\u4e2a\u5b57\u7b26\u4e32\u8d4b\u7ed9\u4e00\u4e2a\u53d8\u91cf

\u5bf9\u4e8estring\u578b\u7684\u53d8\u91cf\uff0c\u76f4\u63a5\u8d4b\u503c\u5373\u53ef\uff0c\u5982string str="abcde";\u4f7f\u7528string\u7c7b\u9700\u8981\u4f7f\u7528\u5934\u6587\u4ef6#include
\u5bf9\u4e8echar\u6570\u7ec4\u578b\u7684\u53d8\u91cf\uff0c\u5728\u58f0\u660e\u65f6\u53ef\u4ee5\u76f4\u63a5\u8d4b\u503c\uff0c\u5982char str[] = "abcde"\uff0c
\u5bf9\u4e8echar\u6570\u7ec4\u578b\u7684\u53d8\u91cf\uff0c\u5728\u975e\u58f0\u660e\u7684\u65f6\u5019\u8d4b\u503c\u65f6\uff0c\u4e0d\u80fd\u76f4\u63a5\u8d4b\u503c\uff0c\u5982char str[64];str = "abcde";\u662f\u4e0d\u5141\u8bb8\u7684\uff0c\u9700\u8981\u501f\u52a9strcpy\u51fd\u6570\u8fdb\u884c\u8d4b\u503c\uff0c\u9700\u8981\u4f7f\u7528\u5934\u6587\u4ef6#include \u3002\u4f7f\u7528\u65b9\u6cd5\uff1a
char str[64];strcpy(str, "abcde");//\u5c06abcde\u62f7\u8d1d\u5230str\u6570\u7ec4\u4e2d\u3002

\u4e0d\u80fd,\u4e00\u4e2a\u5b57\u7b26\u578b\u53d8\u91cf\u53ea\u80fd\u5b58\u653e\u4e00\u4e2a\u5b57\u7b26,\u60f3\u5b58\u653e\u5b57\u7b26\u4e32\u8981\u7528\u5230\u5b57\u7b26\u578b\u6570\u7ec4,\u4fd7\u79f0\u5b57\u7b26\u4e32.

#include<iostream>

#include<string>

using namespace std;

int main()

{

string  str="value is ";

int a=3;

char ch=(char)(a+int('0'));

str+=ch;

cout<<str;

return 0;

}

定义如下：
string m;
cin>>m;
cout<<m<<endl;

屏幕输入asdassdsa
输出是asdassdsa
但是输入asd sds dsd（有空格）
输出只有asd。

用字符串输出流

头文件： #include<sstream>
类: ostringstream

#include<sstream>
#include<iostream>

int main() {
std::ostringstream out;
out << "The number is " << 3;
std::cout << out.str() << std::endl;
}

#include <sstream>
#include <iostream>
using namespace std;
int main() {
	stringstream sstr;
	int a = 3;
	sstr << "value is " << a <<"
";
	cout << sstr.str() << endl;
	return 0;
}

char string[100];

int a=3;
sprintf(string,"value is %d",a);
输出string就可以得到
value is 3

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