C Program for LowerCase to UpperCase and vice-versa

Here is the program to convert a string to uppercase in C language,

Example

 Live Demo

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

int main() {
   char s[100];
   int i;
   printf("\nEnter a string : ");
   gets(s);

   for (i = 0; s[i]!='\0'; i++) {
      if(s[i] >= 'a' && s[i] <= 'z') {
         s[i] = s[i] - 32;
      }
   }
   printf("\nString in Upper Case = %s", s);
   return 0;
}

Output

Here is the output

Enter a string : hello world!
String in Upper Case = HELLO WORLD!

In the above program, the actual code of conversion of string to upper case is present in main() function. An array of char type s[100] is declared which will store the entered string by the user.

Then, for loop is used to convert the string into upper case string and if block is used to check that if characters are in lower case then, convert them in upper case by subtracting 32 from their ASCII value.

for (i = 0; s[i]!='\0'; i++) {

   if(s[i] >= 'a' && s[i] <= 'z') {
      s[i] = s[i] -32;
   }
}

Here is the program to convert a string to lowercase in C language,

Example

 Live Demo

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

int main() {
   char s[100];
   int i;

   printf("\nEnter a string : ");
   gets(s);

   for (i = 0; s[i]!='\0'; i++) {
      if(s[i] >= 'A' && s[i] <= 'Z') {
         s[i] = s[i] + 32;
      }
   }

   printf("\nString in Lower Case = %s", s);
   return 0;
}

Output

Here is the output

Enter a string : HELLOWORLD
String in Lower Case = helloworld

In the above program, the actual code of conversion of string to lowercase is present in main()function. An array of char type s[100] is declared which will store the entered string by the user.

Then for loop is used to convert the string into lower case string and if block is used to checkthat if characters are in uppercase then, convert them in lowercase by adding 32 to their ASCII value.

for (i = 0; s[i]!='\0'; i++) {
   if(s[i] >= 'A' && s[i] <= 'Z') {
      s[i] = s[i] + 32;
   }
}

Ankith Reddy

Updated on 25-Jun-2020 09:35:36

• Related Questions & Answers
• Return element-wise a copy of the string with uppercase characters converted to lowercase and vice versa in Numpy
• C++ Program to Convert Binary Number to Decimal and vice-versa
• C++ Program to convert Octal Number to Decimal and vice-versa
• C++ Program to Convert Binary Number to Octal and vice-versa
• C++ Program to Convert Km/hr to miles/hr and vice versa
• Converting string to number and vice-versa in C++
• Binary to decimal and vice-versa in Python
• Java program to convert a string to lowercase and uppercase.
• Convert from any base to decimal and vice versa in C++
• Converting Strings to Numbers and Vice Versa in Java.
• Convert string to DateTime and vice-versa in Python
• Adding Tuple to List and vice versa in Python
• Java Program to Convert the LinkedList into an Array and vice versa
• Java Program to Convert the ArrayList into a string and vice versa
• Program to convert speed in km/hr to m/sec and vice versa in C++