C-Program to Print number of white spaces in sentence

#include<stdio.h>

#include<string.h>

int main()

{

    int i,spaces=0;

    char str[100];

    printf("Enter a sentence to know number of white spaces\n");

    gets(str);

    for(i=0;i<strlen(str);i++)

    {

        if(str[i]==' ')

        {

            spaces++;

        }

    }

    printf("%d\n",spaces);

return 0;

}