How to have a function output a string, not just the first word-CodePudding

I'm writing a function to capitalize every lowercase character in a string. It takes a string from the user and that is the input to the function. My program works if the user doesn't enter spaces, but when there is a space in the string, the function ends.

#include <stdio.h>

char *uppercase(char *c) {
    int i = 0;
    while (c[i] != '\0') {
        if (123 > c[i] && c[i] > 96)
            c[i] = c[i] - 'a'   'A';
        i  ;
    }
    return c;
}

int main() {
    char input[100];
    printf("Enter the phrase: ");
    scanf("%s", input);
    printf("%s", uppercase(input));
    return 0;
}

Examples:

Input: test test
Output: TEST

Input: Hello
Output: HELLO

Input: How are you
Output: HOW

I think it has to do with the while statement? Thanks for the help.

CodePudding user response：

The problem is not in the while statement, but rather due to the scanf() format: %s reads a single word from the input, leaving the rest of the line in the stdin buffer. Note also that typing a word with more than 99 characters will cause undefined behavior because scanf() will write beyond the end of the input array. Using