Question

How to convert lowercase letter to uppercase and uppercase letter to lowercase in C

Answer 1

#include <stdio.h>
  
int main(void)
{
    char s[] = "The Last Line Of Code";
    int i;
    
	// A - 65 .. Z - 90 (ASCII)
 	// a - 97 .. Z - 122 (ASCII)
    // 97 - 65 = 32
	
    while (s[i])
	{
        if (s[i] >= 97 && s[i] <= 122)
			s[i] = s[i] - 32;
		else if (s[i] >= 65 && s[i] <= 90)
				s[i] = s[i] + 32;
		i++;
	}
	
	puts(s);
     
    return 0;
}
  
   
/*
     
run:
     
tHE lAST lINE oF cODE

*/

 

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Answer 2

#include <stdio.h>
  
int main(void)
{
    char s[] = "The Last Line Of Code";
    int i;
    
	// A - 65 .. Z - 90 (ASCII)
 	// a - 97 .. Z - 122 (ASCII)
    // 97 - 65 = 32
	
    while (s[i])
	{
        if (s[i] >= 'a' && s[i] <= 'z')
			s[i] = s[i] - 32;
		else if (s[i] >= 'A' && s[i] <= 'Z')
				s[i] = s[i] + 32;
		i++;
	}
	
	puts(s);
     
    return 0;
}
  
   
/*
     
run:
     
tHE lAST lINE oF cODE

*/

 

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