C program to count number of SPACES in string

#include<stdio.h>

int main()
{
    char a[100];
    int space=0, i;

    printf("Write a sentence: \n");
    gets(a);

    for(i=0; a[i]!='\0'; i++)
    {
        if( a[i]==' ' )
        {
            space+=1;
        }
    }


    printf("The number of  spaces in the sentence are : %d",space);


    return 0;
}