strchr()

原型：

extern char *strchr(const char *s,char c);

头文件：

#include <string.h>

功能：查找字符串s中首次出现字符c的位置

说明：返回首次出现c的位置的 指针，如果s中不存在c则返回 NULL。

返回值：Returns the address of the first occurrence of the character in the string if successful, or NULL otherwise

函数实现:

char* strchr(char* s,char c)
{
        while(*s != '\0' && *s != c) {
                ++s;
        }
        return *s == c ?s:NULL;
}

使用例子:

例1:

#include <string.h>
#include <stdio.h>

int main(void)
{
        char string[17];
        char *ptr, c = 'r';

        strcpy(string, "This is a string");

        ptr = strchr(string, c);
        if (ptr) /* ptr - string, means the address offset from string to ptr. */
                printf("The character %c is at position: %d\n", c, ptr-string);
        else
                printf("The character was not found\n");
        return 0;
}

运行结果:

$ ./a.out
The character r is at position: 12

例2:

#include <stdio.h>
#include <string.h>
int main()
{
        char temp[32];

        memset(temp,0,sizeof(temp));

        strcpy(temp,"Golden Global View");
        char *s = temp;
        char *p,c='V';

        p=strchr(s,c);
        if(p)
                printf("%s\n",p);
        else
                printf("Not Found!\n");
        return 0;
}

运行结果:

$ ./a.out
View

例3:

#include <stdio.h>
#include <string.h>

void main()
{
        char answer[100],*p;

        printf("Type something:\n");
        fgets(answer,sizeof answer,stdin);

        if((p = strchr(answer,'\n')) != NULL)
                *p = '\0';
        printf("You typed \"%s\"\n",answer);
}

运行结果:

$ ./a.out
Type something:
hello, how are you?
You typed "hello, how are you?"