linux 环境变量PATH设置

43课时的内容：gets/puts/scanf/fgets/fputs

44课时的内容：strlen/strcat/strcmp/strncmp/strstr/sprintf

gets()是获取字符串的输入，例如：

#inculde <stdio.h>
int main(void)
{
char abc[100] = {0};
gets(abc);
puts(abc);  //  equal to printf("%s\n",abc);
}

scanf()和gets() 的区别就在于如果遇到空格，scanf()就会终止打印，gets()则不会。
对于fgets()和fputs() ,用法如下：

#include <stdio.h>
int main(void)
{
char str[100] = {0};
//    printf("%s\n",gets(str));
fgets(str,100,stdin);
fputs(str,100,stdout);
return 0;
}

strlen():

#include <stdio.h>
#include <string.h>
int main(void)
{
char abc[100] = {0};
gets(abc);
printf("%d:%s\n",strlen(abc),abc);
return 0;
}

strcat():

#include <stdio.h>
#include <string.h>
int main(void)
{
char abc[100] = {0};
char abc1[120] = "
gets(abc);
strcat(abc1,abc);
puts(abc1);
return 0;
}

strcmp():

#include <stdio.h>
#include <string.h>
int main(void)
{
char abc[100] = {0};
char abc1[130] = "
gets(abc);
if(strNcmp(abc1,abc，N) == 0)  //strncmp就是多了个数，只比较前n个字符
{
printf("相等\n");
} else{
printf(不相等\n");
}
return 0;
}

strstr():

#include <stdio.h>
#include <string.h>
int main(void)
{
char abc[100] = {0};
char abc1[200] = "
char * t = NULL;
gets(abc);
if(t = strstr(abc1,abc))
{
printf("%s\n",t);
}
return 0;
}

sprintf()

#include <stdio.h>
#include <string.h>
int main(void)
{
char abc[100] = {0};
char abc1[200] = "
gets(abc);
sprintf(abc1,"%s %s",abc1,abc);
puts(abc1);    //或者是printf("%s\n",abc1);
}