sizeof 和 memset

最新推荐文章于 2023-04-05 14:59:13 发布

转载最新推荐文章于 2023-04-05 14:59:13 发布 · 810 阅读

文章标签：

#buffer #function #struct #c

本文通过示例介绍如何使用 memset 函数设置内存值，并探讨了 C 语言中结构体成员对齐的问题及其对 sizeof 运算符的影响。

// Example of the sizeof keyword size_t i = sizeof( int ); struct align_depends { char c; int i; }; size_t size = sizeof(align_depends); // The value of size depends on // the value set with /Zp or // #pragma pack int array[] = { 1, 2, 3, 4, 5 }; // sizeof( array ) is 20 // sizeof( array[0] ) is 4 size_t sizearr = // Count of items in array sizeof( array ) / sizeof( array[0] );

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/* MEMSET.C: This program uses memset to * set the first four bytes of buffer to "*". */ #include <memory.h> #include <stdio.h> void main( void ) { char buffer[] = "This is a test of the memset function"; printf( "Before: %s/n", buffer ); memset( buffer, '*', 4 ); printf( "After: %s/n", buffer ); }

输出：

Before: This is a test of the memset function
After: **** is a test of the memset function