Question

Write a program that asks the user to enter a sentence and then switch all lower case letters to capitals and all upper case letters to lower. HINT: use the ASC function to tell your program which letters are upper or lower case so you can switch them. Your program should allow for multiple test cases.

Answer 1

Below is the solution:

code:

#include <stdio.h>

int main() {
   char s[100]; //declare the char array
   printf("\nEnter a string : "); //ask to enter the string
   gets(s); //get from keyboard
   ASC(s); //call the function to uppercase to lower and lower case to upper

   return 0;
}
void ASC(char s[100]){
    int i; //declare the value
    printf("\nString: "); //print
    for (i = 0; s[i]!='\0'; i++) { //loop each of the char until null
      if(s[i] >= 'a' && s[i] <= 'z') { //check for the lower case
         s[i] = s[i] - 32; //subtract the value to print the uppercase
         printf("%c", s[i]); //print the character
      }
      else if(s[i] >= 'A' && s[i] <= 'Z') {
         s[i] = s[i] + 32; //add the value to print the lowercase
         printf("%c", s[i]); //print the character
      }
      else if(s[i] == ' ') {
          printf("%c",s[i]); //prints the space
      }
      else{ //prints the other characters
          printf("%c",s[i]); //prints
      }
   }
}

sample output:

Enter a string : This is The tESt sTriNg.
String: tHIS IS tHE TesT StRInG.