C++中怎样将一个文件的内容读取到string类型的字符串中。谢谢!

2024-12-01 10:11:37
推荐回答(3个)
回答1:

先将文件全部读入 char* 变量。再用 string 类 构建函数建一个string 对象,在把 char* 内容放入。

下面是将文件全部读入char * buffer;

/* fread example: read an entire file */
#include
#include
int main () {
FILE * pFile;
long lSize;
char * buffer;
size_t result;
pFile = fopen ( "myfile.bin" , "rb" );
if (pFile==NULL) {fputs ("File error",stderr); exit (1);}
// obtain file size:
fseek (pFile , 0 , SEEK_END);
lSize = ftell (pFile);
rewind (pFile);
// allocate memory to contain the whole file:
buffer = (char*) malloc (sizeof(char)*lSize);
if (buffer == NULL) {fputs ("Memory error",stderr); exit (2);}
// copy the file into the buffer:
result = fread (buffer,1,lSize,pFile);
if (result != lSize) {fputs ("Reading error",stderr); exit (3);}
/* the whole file is now loaded in the memory buffer. */
// terminate
fclose (pFile);
free (buffer);
return 0;
}

构建函数建一个string 对象,把 char * buffer 内容存入 程序部分,请自己补充:
#include
#include
#include
using namespace std;
#include
// 插入上面程序 .....
// 补充
string sss;
sss.assign(buffer,result);
cout << sss << endl;

回答2:

fstream fs( "file.txt" ) ; // 创建个文件流对象,并打开"file.txt"
stringstream ss ; // 创建字符串流对象
ss << fs.rdbuf() ; // 把文件流中的字符输入到字符串流中
string str = ss.str() ; // 获取流中的字符串

回答3:

用文件流 需要头文件cstdio

freopen("a.in","r",stdin);
freopen(a.out","w",stdout);
string i;
getline(cin,i,'\n');
cout<
fclose(stdin);
fclose(stdout);

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