もう一つ作ったよ

#include <stdio.h>

void chomp(char *s) {
size_t len = strlen(s);
if (0 < len && s[len - 1] == '\n') {
s[len - 1] = '\0';
}
}
int main(int argc, char * argv[])
{
char buf[512];
FILE *pf;

for (; ; ) {
if(!fgets(buf, sizeof(buf), stdin) || *buf == '\n') {
break;
}
chomp(buf);
pf = fopen("temp.c", "w");
if (!pf) {
return 0;
}
fprintf(pf, "#include <stdio.h>\nint main(void){printf(\"%%f\\n\", (double)%s); return 0;}", buf);
fclose(pf);
system("gcc -o temp temp.c");
system("./temp");
}
return 0;
}