查找给定字符串中第 n 次出现的字符
给定字符串 str 、字符 ch 和值 N ，任务是找到给定字符串中给定字符第 N 次出现的索引。如果不存在这种情况，打印-1。
示例:
输入: str = "Geeks "，ch = 'e '，N = 2 T3】输出: 2
输入: str = "GFG "，ch = 'e '，N = 2 输出: -1
进场:
- 逐个字符遍历字符串。
- 检查每个字符是否与给定字符匹配。
- 如果计数与给定字符匹配，则将计数增加 1。
- 如果计数等于 N，则返回最新找到的索引
- 如果遍历后计数与 N 不匹配，返回-1
下面是上述方法的实现:
C++
// C++ implementation to find the
// Nth occurrence of a character
#include <bits/stdc++.h>
using namespace std;
// Function to find the
// Nth occurrence of a character
int findNthOccur(string str,
char ch, int N)
{
int occur = 0;
// Loop to find the Nth
// occurrence of the character
for (int i = 0; i < str.length(); i++) {
if (str[i] == ch) {
occur += 1;
}
if (occur == N)
return i;
}
return -1;
}
// Driver Code
int main()
{
string str = "geeks";
char ch = 'e';
int N = 2;
cout << findNthOccur(str, ch, N);
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java implementation to find the
// Nth occurrence of a character
import java.util.*;
class GFG
{
// Function to find the
// Nth occurrence of a character
static int findNthOccur(String str,
char ch, int N)
{
int occur = 0;
// Loop to find the Nth
// occurrence of the character
for (int i = 0; i < str.length(); i++)
{
if (str.charAt(i) == ch)
{
occur += 1;
}
if (occur == N)
return i;
}
return -1;
}
// Driver Code
public static void main(String[] args)
{
String str = "geeks";
char ch = 'e';
int N = 2;
System.out.print(findNthOccur(str, ch, N));
}
}
// This code is contributed by 29AjayKumar
Python 3
# Python3 implementation to find the
# Nth occurrence of a character
# Function to find the
# Nth occurrence of a character
def findNthOccur(string , ch, N) :
occur = 0;
# Loop to find the Nth
# occurrence of the character
for i in range(len(string)) :
if (string[i] == ch) :
occur += 1;
if (occur == N) :
return i;
return -1;
# Driver Code
if __name__ == "__main__" :
string = "geeks";
ch = 'e';
N = 2;
print(findNthOccur(string, ch, N));
# This code is contributed by AnkitRai01
C
// C# implementation to find the
// Nth occurrence of a character
using System;
class GFG
{
// Function to find the
// Nth occurrence of a character
static int findNthOccur(String str,
char ch, int N)
{
int occur = 0;
// Loop to find the Nth
// occurrence of the character
for (int i = 0; i < str.Length; i++)
{
if (str[i] == ch)
{
occur += 1;
}
if (occur == N)
return i;
}
return -1;
}
// Driver Code
public static void Main(String[] args)
{
String str = "geeks";
char ch = 'e';
int N = 2;
Console.Write(findNthOccur(str, ch, N));
}
}
// This code is contributed by PrinciRaj1992
java 描述语言
<script>
// Javascript implementation to find the
// Nth occurrence of a character.
// Function to find the
// Nth occurrence of a character
function findNthOccur(str, ch, N)
{
var occur = 0;
// Loop to find the Nth
// occurrence of the character
for (var i = 0; i < str.length; i++) {
if (str[i] == ch) {
occur += 1;
}
if (occur == N)
return i;
}
return -1;
}
var str = "geeks";
var ch = 'e';
var N = 2;
document.write( findNthOccur(str, ch, N));
// This code is contributed by SoumikMondal
</script>
Output:
2
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