C语言 小技巧函数方法总结

1.使用^(异或) 不引入第三变量交换两个变量的值。

/* 交换 int a 和 int b 的值*/
#include <stdio.h>

int main(int argc, char *argv[])
{
        int a = 11;
        int b = 22;

        a = a^b;
        b = a^b;
        a = a^b;

        printf("a = %d\n",a);
        printf("b = %d\n",b);
        return 0;
}

运行结果
[root@192 clang]# gcc changeVal.c
[root@192 clang]# ./a.out
a = 22
b = 11

 

2.字符串操作

/* 将字符串path = “/root/tmp/as.scv” 截取为 /root/tmp/as后，再拼接添加_static 为 /root/tmp/as_static */
#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[])
{
        char *path = "/root/tmp/as.scv";
        char *newname = "static";
        char last[300] = {0};

        strncpy(last,path,(strlen(path) - strlen(strrchr(path,'.'))));
        sprintf(last,"%s_%s",last,newname);

        printf("newname = %s\n",last);

        return 0;
}


运行结果：

[root@192 clang]# gcc stringtes.c
[root@192 clang]# ./a.out
newname = /root/tmp/as_static