супер легкая

#include <stdio.h>
#include <ctype.h>
#define SIZE 20


int main()
{
    int i,j,inword = 0;
    char str[SIZE]="abc def ghk lmn opq";


    for(i=0;i<SIZE;i++)
    {
        if(!inword&&isalpha(str[i]))//first letter in word
            {
                str[i] = toupper(str[i]);
                inword=1;
            }
        else if(inword&&!(isalpha(str[i])))//first non-alpha after word
            {
                str[i-1] = toupper(str[i-1]);
                inword=0;
            }

    }

    for(i=0;i<SIZE;i++)
        printf("%c  ",(str[i]));


    return 0;
}