strstr
- Returns a pointer to the first occurrence of str2 in str1, or a null pointer if str2 is not part of str1.
- 查詢 substr 所指的空終止位元組字串在 str 所指的空終止位元組字串中的首次出現。不比較空終止字元。
- 若 str 或 substr 不是指向空終止位元組字串的指標，則行為未定義。
char *strstr(const char *haystack, const char *needle)
Parameters
haystack
- C string to be scanned.
- 要被檢索的 C 字串。
needle
- C string containing the sequence of characters to match.
- 在 haystack 字串內要搜尋的小字串。
Return Value
- A pointer to the first occurrence in str1 of the entire sequence of characters specified in str2, or a null pointer if the sequence is not present in str1.
- 該函式返回在 haystack 中第一次出現 needle 字串的位置，如果未找到則返回 null。
Example
//
// Created by zhangrongxiang on 2017/8/15 14:15.
// Copyright (c) 2017 ZRC . All rights reserved.
//
//#include <syslib.h>
#include <string.h>
#include <stdio.h>
//C 庫函式 char *strstr(const char *haystack, const char *needle) 在字串 haystack 中查詢第一次出現字串 needle 的位置，不包含終止符 ` `。
void find_str(char const *str, char const *substr) {
char *pos = strstr(str, substr);
if (pos) {
printf("found the string `%s` in `%s` at position: %ld; result: %s
", substr, str, pos - str, pos);
} else {
printf("the string `%s` was not found in `%s`
", substr, str);
}
}
int main() {
char *s = "GoldenGlobalView";
char *l = "lob";
char *p;
//返回值：若str2是str1的子串，則返回str2在str1的首次出現的地址；
// 如果str2不是str1的子串，則返回NULL。
p = strstr(s, l);
if (p)
//lobalView
printf("%s
", p);
else
printf("NotFound!
");
char *str = "one two three";
find_str(str, "two"); //found the string `two` in `one two three` at position: 4; result: two three
find_str(str, ""); // found the string `` in `one two three` at position: 0; result: one two three
find_str(str, "nine");// the string `nine` was not found in `one two three`
find_str(str, "n"); // found the string `n` in `one two three` at position: 1; result: ne two three
char str2[] = "This is a simple string";
char *pch;
pch = strstr(str2, "simple");
strncpy (pch, "sample", 6);
puts(str2);//This is a sample string
puts(pch);//sample string
return 0;
}
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