如何使用sprintf追加字符串？

Question

我正面临着sprintf的一个严重问题.

假设我的代码片段是:

sprintf(Buffer,"Hello World");
sprintf(Buffer,"Good Morning");
sprintf(Buffer,"Good Afternoon");
.
.
.

几百个短跑......

如果我这样做,它会被覆盖.

如何避免使用sprintf覆盖.如果我在最后给出printf,我想看到所有的线条.

Answer 1

你需要:

sprintf(Buffer,"Hello World");
sprintf(Buffer + strlen(Buffer),"Good Morning");
sprintf(Buffer + strlen(Buffer),"Good Afternoon");

当然,你需要你的缓冲区足够大.

Answer 2

int length = 0;
length += sprintf(Buffer+length, "Hello World");
length += sprintf(Buffer+length, "Good Morning");
length += sprintf(Buffer+length, "Good Afternoon");

这是一个对错误有抵抗力的版本.如果您在发生错误时不关心它,只要您可以继续沿着您的快乐方式行事,这将非常有用.

int bytes_added( int result_of_sprintf )
{
    return (result_of_sprintf > 0) ? result_of_sprintf : 0;
}

int length = 0;
length += bytes_added(sprintf(Buffer+length, "Hello World"));
length += bytes_added(sprintf(Buffer+length, "Good Morning"));
length += bytes_added(sprintf(Buffer+length, "Good Afternoon"));

Answer 3

为安全起见(缓冲区溢出)我建议使用snprintf()

const int MAX_BUF = 1000;
char* Buffer = malloc(MAX_BUF);

int length = 0;
length += snprintf(Buffer+length, MAX_BUF-length, "Hello World");
length += snprintf(Buffer+length, MAX_BUF-length, "Good Morning");
length += snprintf(Buffer+length, MAX_BUF-length, "Good Afternoon");

Answer 4

一个snprintfcat()包装snprintf():

size_t 
snprintfcat(
    char* buf,
    size_t bufSize,
    char const* fmt,
    ...)
{
    size_t result;
    va_list args;
    size_t len = strnlen( buf, bufSize);

    va_start( args, fmt);
    result = vsnprintf( buf + len, bufSize - len, fmt, args);
    va_end( args);

    return result + len;
}

Answer 5

使用返回值 sprintf()

Buffer += sprintf(Buffer,"Hello World");
Buffer += sprintf(Buffer,"Good Morning");
Buffer += sprintf(Buffer,"Good Afternoon");

Answer 6

你为什么要使用sprintf字符串连接时,有一些方法旨在专门为你所需要的,如strcat和strncat？

Answer 7

我发现以下方法效果很好。

sprintf(Buffer,"Hello World");
sprintf(&Buffer[strlen(Buffer)],"Good Morning");
sprintf(&Buffer[strlen(Buffer)],"Good Afternoon");

Answer 8

小完整代码示例

仅使用 flat plain stdio标准库

#include <stdio.h>
int main()
    {
    char c[1024];
    int  i=0;

    i+=sprintf(c+i,"We "   );
    i+=sprintf(c+i,"Love " );
       sprintf(c+i,"Coding");

    printf("%s",c);
    }

输出：我们热爱编码