C库函数 - fabs() C库函数 - sqrt() C库宏 - va_start() C库函数 - fabs() #include <stdio.h> #include <math.h> int main () { int a, b; a = 1234; b = -344; printf("The absolute value of %d is %lf\n", a, fabs(a)); printf("The absolute value of %d is %lf\n", b, fabs(b)); return(0); } C库函数 - sqrt() C库宏 - va_start()