一个关于sprintf的问题。看看这个结果怎样分析！

2009-08-13 05:48:06 252 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

sprintf做字符串拼接的问题分析 sprintf实现字符串拼接，尤其是本例中自身拼接，是不安全的实现，gcc -D_FORTIFY_SOURCE=2选项会导致行为上的差异。阅读详情

#include <stdio.h>

void main( void )
{
char buffer[200], s[] = "computer", c = 'l';
int i = 35, j;
float fp = 1.7320534f;

/* Format and print various data: */

printf( "Output:\n%s\ncharacter count = %d\n", buffer, j );

j = sprintf( buffer, "\tString: %s\n", s );
printf( "Output:\n%s\ncharacter count = %d\n", buffer, j );

j += sprintf( buffer + j, "\tCharacter: %c\n", c );
printf( "Output:\n%s\ncharacter count = %d\n", buffer, j );

j += sprintf( buffer + j, "\tInteger: %d\n", i );
printf( "Output:\n%s\ncharacter count = %d\n", buffer, j );

j += sprintf( buffer + j, "\tReal: %f\n", fp );
printf( "Output:\n%s\ncharacter count = %d\n", buffer, j );
}

结果如下：

Output:
烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫
烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫
烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫烫?
character count = 0
Output:
String: computer

character count = 21
Output:
String: computer
Character: l

character count = 35
Output:
String: computer
Character: l
Integer: 35

character count = 50
Output:
String: computer
Character: l
Integer: 35
Real: 1.732053

character count = 71
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