How to convert lowercase to uppercase in c language

In C language, ASCII code is used to convert lowercase letters into uppercase letters. The ASCII code value range for lowercase letters is 97-122, and for uppercase letters is 65-90. Therefore, by subtracting 32 from the ASCII code value of the lowercase letters, the corresponding ASCII code value of the uppercase letters can be obtained.

In C language, you can use ASCII code to convert lowercase letters to uppercase letters. In the ASCII code table, the ASCII code value range of lowercase letters a-z is 97-122, while the ASCII code value range of the corresponding uppercase letters A-Z is 65-90. Therefore, we only need to subtract 32 (97-65=32) from the ASCII code value of the lowercase letters to get the corresponding ASCII code value of the uppercase letters.

The following is a simple C language function for converting lowercase letters to uppercase letters:

c

#include <stdio.h>  
  
char to_upper(char c) {  
    if (c >= &#39;a&#39; && c <= &#39;z&#39;) {  
        return c - &#39;a&#39; + &#39;A&#39;;  
    }  
    return c;  
}  
  
int main() {  
    char ch = &#39;b&#39;;  
    printf("小写字母 %c 转换为大写字母是 %c\n", ch, to_upper(ch));  
    return 0;  
}

In this example, we define a function called to_upper Function that takes a character as an argument and returns the uppercase version of that character (if it is lowercase). In the main function, we call the to_upper function to convert the lowercase letter b to an uppercase letter and print the result.

Note that in the to_upper function, we first check whether the incoming characters are lowercase letters. If it is, we convert it to uppercase; if not, we just return it. Doing this ensures that our function handles all types of characters correctly.

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