程序代码：

#include < stdio.h >
#include < stdlib.h >
void main ( )
{
    char string [81];
    int i, sum = 0;
    char c;
    gets ( string );
    for ( i = 0; ( c = string[i]) != '\n'; i++ )
        sum = sum  +1;
    printf ( "%d", sum );
    system ( "pause" );
}