Reads input until end-of-file and echoes it to the display, convert to uppercase or lowercase - C String

Description

Reads input until end-of-file and echoes it to the display, convert to uppercase or lowercase

Demo Code

#include <stdio.h>  
#include <ctype.h>  
  
int main(int argc, char *argv[])  {  
    char mode = 'p';  
    int ok = 1;  
    int ch;  //from   w  w w .j a  v  a2  s.c  o m
      
    if (argc > 2){  
        printf("Usage: %s [-p | -u | -l]\n", argv[0]);  
        ok = 0;                /* skip processing input */  
    }else if (argc == 2) {  
        if (argv[1][0] != '-') {  
            printf("Usage: %s [-p | -u | -l]\n", argv[0]);  
            ok = 0;  
        }  
        else   
            switch(argv[1][1]) {  
                case 'p':  
                case 'u':  
                case 'l': mode = argv[1][1];  
                          break;  
                default :    printf("%s is an invalid flag; ", argv[1]);  
                             printf("using default flag (-p).\n");  
            }  
    }  
      
    if (ok)  
        while ((ch = getchar() ) != EOF)  
        {  
            switch(mode)  
            {  
                case 'p'     :    putchar(ch);  break;  
                case 'u'     :    putchar(toupper(ch));  break;  
                case 'l'     :    putchar(tolower(ch));  
            }  
        }  
                              
    return 0;  
}

Result

• Previous
• Next

Related Tutorials

• Print each input character and its ASCII decimal value.
• Returns the first non- whitespace character encountered.
• Report the average number of letters per word.
• Find the Lengths of strings
• Strlen() takes a reference to a string and returns the numeric string length up to the NULL or terminating character, but not including the NULL character.