C/C++ :: Find Length Of First Sentence In Input String

I have a question about finding the length of first sentence in an input string.

For example, let the input string be: dream in code. community learning

The length of first sentence is 13 (blanks are included). My question is how to create conditions for multiple punctuation signs (!,?)? If while loop goes like:

while((str[i]!='.')||(str[i]!='!')||(str[i]!='?'))

it gives me an error for infinite loop.

Code:
#include<stdio.h>
int main() {
char str[100];int i=0,br=0;
printf("enter a string:
");
gets(str);

[Code] ....