C Program to find Last Occurrence of a Character in a String

How to write a C Program to find Last Occurrence of a Character in a String with an example?.

C Program to find Last Occurrence of a Character in a String Example 1

This program allows the user to enter a string (or character array), and a character value. Next, it will search and find the last occurrence of a character inside a string using If Else Statement.

/* C Program to find Last Occurrence of a Character in a String */
 
#include <stdio.h>
#include <string.h>
 
int main()
{
  	char str[100], ch;
  	int i, index;
  	index = -1;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	printf("\n Please Enter the Character that you want to Search for :  ");
  	scanf("%c", &ch);
  	
  	for(i = 0; i <= strlen(str); i++)
  	{
  		if(str[i] == ch)  
		{
  			index = i;	
 		}
	}
    if(index == -1)
  	{
  		printf("\n Sorry!! We haven't found the the Search Element '%c' ", ch);
	}
	else
	{
		printf("\n The Last Occurrence of the Search Element '%c'' at Position %d ", ch, index + 1);
	}	
  	return 0;
}

First, we used For Loop to iterate each character in a String.

for(i = 0; i <= strlen(str); i++)
{
	if(str[i] == ch)  
	{
		index = i;  	
	}
}

str[] = Hello World
ch = l
Index = -1

While Loop First Iteration: while (str[ i ] != 0)
The condition is True because str[0] = H.

Within the C Programming While Loop, we used If statement to check whether the str[0] is equal to a user-specified character or not

if(str[i] == ch) => if(H == l)

The above condition is false. So, i will increment, and the Index value is still -1.

Second Iteration: while (str[ 1 ] != 0)
The condition is True because str[1] = e.

if(str[i] == ch) => if(e == l) – condition is false. So, i value will be incremented, and Index value is still -1.

Third Iteration: while (str[ 2 ] != 0) – condition is True because str[2] = l.

if(str[i] == ch) => if(l == l) – condition is True.
Index  = i
index  = 2

Third Iteration: while (str[ 3 ] != 0) – condition is True because str[3] = l.

if(str[i] == ch) => if(l == l) – condition is True.
index  = i = 3

Do the same for remaining iterations.

Next, we used the If Else Statement to check the index value is equal to -1. Here, the condition is False. So, the statement inside the else block will execute.

printf("\n The Last Occurrence of the Search Element '%c' is at Position %d ", ch, i + 1);

Here, i is the index position (start with zero), and i + 1 is the actual position.

C Program to find Last Occurrence of a Character in a String Example 2

This C program for last character occurrence is the same as above. Here, we just replaced the For Loop with While Loop.

/* C Program to find Last Occurrence of a Character in a String */
 
#include <stdio.h>
#include <string.h>
 
int main()
{
  	char str[100], ch;
  	int i, index;
  	i = 0;
  	index = -1;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	printf("\n Please Enter the Character that you want to Search for :  ");
  	scanf("%c", &ch);
  	
  	while(str[i] != '\0')
  	{
  		if(str[i] == ch)  
		{
  			index = i;	
 		}
 		i++;
	}
    if(index == -1)
  	{
  		printf("\n Sorry!! We haven't found the the Search Element '%c' ", ch);
	}
	else
	{
		printf("\n The Last Occurrence of the Search Element '%c'' at Position %d ", ch, index + 1);
	}	
  	return 0;
}

 Please Enter any String :  tutorial gateway

 Please Enter the Character that you want to Search for :  a

 The Last Occurrence of the Search Element 'a'' at Position 15

C Program to find Last Occurrence of a Character in a String Example 3

This C program for last Character occurrence is the same as the first example, but this time we used the Functions concept to separate the logic.

/* C Program to find Last Occurrence of a Character in a String */
 
#include <stdio.h>
#include <string.h>

int Find_LastCharcater(char str[], char ch);

int main()
{
  	char str[100], ch;
  	int index;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	printf("\n Please Enter the Character that you want to Search for :  ");
  	scanf("%c", &ch);
  	
  	index = Find_LastCharcater(str, ch); 
  	
    if(index == -1)
  	{
  		printf("\n Sorry!! We haven't found the Search Character '%c' ", ch);
	}
	else
	{
		printf("\n The Last Occurrence of the Search Element '%c' at Position %d ", ch, index + 1);
	}	
  	return 0;
}

int Find_LastCharcater(char str[], char ch)
{
	int i, index;
	index = -1;
	
	for(i = 0; str[i] != '\0'; i++)
	{
		if(str[i] == ch)
		{
			index = i;
		}  
	}
	return index;
}

 Please Enter any String :  learn c programming

 Please Enter the Character that you want to Search for :  n

 The Last Occurrence of the Search Element 'n' at Position 18 

C Program to find Last Occurrence of a Character in a String Example 4

This program is same as the first example, but this time we are using the pointers concept.

/* C Program to find Last Occurrence of a Character in a String */
 
#include <stdio.h>
#include <string.h>

int Find_LastCharcater(char *str, char ch);

int main()
{
  	char str[100], ch;
  	int index;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	printf("\n Please Enter the Character that you want to Search for :  ");
  	scanf("%c", &ch);
  	
  	index = Find_LastCharcater(str, ch); 
  	
    if(index == -1)
  	{
  		printf("\n Sorry!! We haven't found the Search Character '%c' ", ch);
	}
	else
	{
		printf("\n The Last Occurrence of the Search Element '%c' at Position %d ", ch, index + 1);
	}	
  	return 0;
}

int Find_LastCharcater(char *str, char ch)
{
	int i, index;
	i = 0;
	index = -1;
	
	while(*str)
	{
		if(*str == ch)
		{
			index = i;
		} 
		i++;
		str++; 
	}
	return index;
}

 Please Enter any String :  welcome to tutorial gateway

 Please Enter the Character that you want to Search for :  e

 The Last Occurrence of the Search Element 'e' at Position 24