Algorithm
-
Input:
- Accept the main string (
mainString
) and the substring (subString
) as input.
- Accept the main string (
-
Initialization:
- Initialize two variables:
mainLength
to store the length of the main string, andsubLength
to store the length of the substring.
- Initialize two variables:
-
Loop through the main string:
- Use a loop to iterate through each character of the main string from index 0 to
mainLength - subLength
.
- Use a loop to iterate through each character of the main string from index 0 to
-
Check for substring match:
- For each index
i
in the loop, compare the substring starting from indexi
in the main string with the given substring. - If they match, the substring is found in the main string.
- For each index
-
Output:
- If a match is found, print or return a message indicating that the substring is present.
- If no match is found after iterating through the entire string, print or return a message indicating that the substring is not present.
Code Examples
#1 Code Example- Check if a string contains a substring using contains()
Code -
Java Programming
class Main {
public static void main(String[] args) {
// create a string
String txt = "This is Programiz";
String str1 = "Programiz";
String str2 = "Programming";
// check if name is present in txt
// using contains()
boolean result = txt.contains(str1);
if(result) {
System.out.println(str1 + " is present in the string.");
}
else {
System.out.println(str1 + " is not present in the string.");
}
result = txt.contains(str2);
if(result) {
System.out.println(str2 + " is present in the string.");
}
else {
System.out.println(str2 + " is not present in the string.");
}
}
}
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Output
Programiz is present in the string.
Programming is not present in the string.
Programming is not present in the string.
#2 Code Example- Check if a string contains a substring using indexOf()
Code -
Java Programming
class Main {
public static void main(String[] args) {
// create a string
String txt = "This is Programiz";
String str1 = "Programiz";
String str2 = "Programming";
// check if str1 is present in txt
// using indexOf()
int result = txt.indexOf(str1);
if(result == -1) {
System.out.println(str1 + " not is present in the string.");
}
else {
System.out.println(str1 + " is present in the string.");
}
// check if str2 is present in txt
// using indexOf()
result = txt.indexOf(str2);
if(result == -1) {
System.out.println(str2 + " is not present in the string.");
}
else {
System.out.println(str2 + " is present in the string.");
}
}
}
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Try With Live Editor
Output
Programiz is present in the string.
Programming is not present in the string.
Programming is not present in the string.
Demonstration
Java Programing Example to Check if a string contains a substring-DevsEnv